Method and apparatus for surgical navigation of a multiple piece construct for implantation

ABSTRACT

A method and apparatus for percutaneous and/or minimally invasive implantation of a construct. The construct may be implanted using a navigation system for planning and execution of a procedure. A plurality of portions of the construct may be interconnected using locations and paths determined and navigated with the navigation system.

FIELD

The present invention relates to surgical navigation for assembly andimplantation of a multi-piece construct into an anatomy; andparticularly to a method and apparatus for percutaneous and/or minimallyinvasive implantation of constructs into a selected portion of ananatomy.

BACKGROUND

Image guided medical and surgical procedures utilize patient imagesobtained prior to or during a medical procedure to guide a physicianperforming the procedure. Recent advances in imaging technology,especially in imaging technologies that produce highly-detailed, two,three, and four dimensional images, such as computed tomography (CT),magnetic resonance imaging (MRI), fluoroscopic imaging, positronemission tomography (PET), and ultrasound imaging (US) has increased theinterest in image guided medical procedures.

Image guided surgical techniques have been used to assist surgeons andindividuals in various surgical procedures. Various image basednavigation systems include U.S. Pat. No. 6,470,207, entitled“Navigational Guidance Via Computer-Assisted Fluoroscopic Imaging”,issued Oct. 22, 2002, which is hereby incorporated by reference in itsentirety; and image based systems such as the STEALTHSTATION, andvarious improvements such as the TREON and ION sold by MedtronicSurgical Navigation Technologies of Louisville, Colo. Generally, theprocedures and instruments used with image guided surgery allow forvisualization or virtual visualization of surgical instruments andvarious anatomical portions in relation to preacquired or real-timeimages. Representations of the instruments and implants are generallysuper-imposed over the preacquired or real-time images of the patientsanatomy. Nevertheless, these systems generally require registration ofthe image data to the patient such that the image data used to guide theprocedure matches the patient's intra-operative orientation known aspatient space.

Various medical procedures may benefit from image-based navigationsystems. For example, a spinal fusion procedure may be performedaccording to various known techniques. For example, an image basednavigation system, such as those discussed above, may be used to assistin a spinal fusion procedure. Nevertheless, the navigation systemgenerally requires the acquisition of a patient image and a registrationof the patient image with the surgical patient space to ensure properguiding and navigation of the instruments and implant portions.Therefore, the image based navigation systems require use of variousimage acquisition components in an operative procedure, such as thefluoroscopic device, a magnetic resonance imaging (MRI) device, or otherimage capturing devices. These images are then registered relative tothe patient, generally using known registration techniques, such asautomatic registration, user guided registration, 2D or 3D registration,point registration and surface registration. Dynamic referencing mayalso be used to track patient movement during the procedure.

In the alternative, a substantially open procedure may be used toperform the spinal fusion, or anterior cruciate ligament replacement,acetabular implantation, femoral implantation, spinal disc nucleasereplacement, spinal disc replacement, and the like. For example, thesoft tissue surrounding the spine, particularly a posterior portion ofthe spine, may be substantially opened or removed such that an “open”view of the spine may be obtained. After the soft tissue has been openedto create the operative passage, the procedure may continue with theuser, such as a surgeon, having a clear view of the surgical area.Nevertheless, the open procedures require a large incision and movementof soft tissue. This large incision, movement of soft tissue, andnecessary closures, often may require an extended recovery.

Open procedures may also be supplemented with various systems, such as adevice to mechanically customize connecting rods by MEDIVISION ofGermany. This system may allow for bending of connecting rods to fix aselected geometry. The selected geometry may be determined using anyappropriate mechanism, such as a coordinated system or registrationsystem to determine the appropriate angle and shape of the rod.

Alternatively, a substantially percutaneous and/or minimally invasiveprocedure may be used to position a construct to perform a spinalfusion. During the percutaneous procedure, the various components of theconstruct are mechanically interconnected or held with an alignmentinstrument. For example, a head of a pedicle screw may be aligned withsuch an instrument. Once aligned, the instrument mechanically guides aconnector member to interconnect with each pedicle screw.

Although this may be achieved with little difficulty when a low orsingle level construct, such as a low number of elements are used, suchas interconnecting two pedicle screws, it becomes more difficult whenattempting to interconnect multi-level constructs, such as more than twopedicle screws. In addition, if the screws are implanted in a selectednon-aligned position, such as required by various procedures, theinterconnection by a connector is also difficult because the alignmentby mechanical means becomes more complex and difficult to achieve.Further, having a constrained geometry increases the complexity. Aconstrained geometry requires the precise alignment of a plurality ofportions that is complex in a percutaneous procedure using mechanicalinterconnections for alignment.

Therefore, it is desirable to provide a method and apparatus forperforming surgical navigation of a percutaneous procedure to implant aselected construct. It is also desirable to provide a surgicalnavigation apparatus and method for generally planning and confirming anassembly of a construct percutaneously to substantially minimize orreduce trauma to the soft tissue and reduce the size of the incisionsrequired to access the anatomical portions. It is also desirable toperform an imageless surgical navigation procedure that does not requireregistration of image data with patient space.

SUMMARY

A method and apparatus for providing a selected multi-componentconstruct relative to other components or to a selected portion of ananatomy. Generally, the apparatii include instruments or elements thatcan be localized by being sensed or detected with various instruments.For example, optical or electromagnetic (EM) localization techniques maybe used to determine the precise location of a selected implantconstruct or implantation instrument. For example, an optical localizercan be positioned relative to an extender extending from implantelement, such as a screw. Similarly, a coil may be positioned in an EMfield such that the position of the coil may be determined by sensingthe induced voltage, and vice versa.

In addition, the apparatii, such as a computer, may allow for theselection of various components that can be implanted to form theselected construct. For example, a predetermined or selected outcome canbe used to provide or form a selected construct from various componentssuch that the selected outcome may be achieved. The various instrumentsmay be used to plan and select intraoperatively the various portions ofthe construct that may be positioned relative to the anatomy.

In addition, the various instruments may be used to guide and track thevarious portions of the construct to ensure that the selected plan isachieved. Therefore, a plan may be formulated prior to the implantationof at least all of the construct to ensure the achievement of theselected outcome. The actual procedure may be performed using theselected plan and the procedure may be monitored, tracked, and navigatedto ensure that the selected outcome is achieved. The whole process maybe performed in an imageless manner and, thereby, without a need toregister images with the patient space.

According to various embodiments a system for use in navigating animplantation of a selected construct is disclosed. The system includes afirst member and a second member of the construct adapted to selectivelyinteract with each other after implantation. A localization element isselectively associated with at least one of the first member and thesecond member. A detector is able to detect the localization elementwhen the localization element is associated with at least one of thefirst member and the second member. Also, a processor is operable toassist in navigation of the second member relative to the first member.The processor is operable to receive position information for at leastone of the first member and the second member from the detector andfurther operable to determine a relative position of the other of the atleast one of the first member and the second member. The relativeposition is operable to allow a navigation of at least one of the firstmember and the second member.

According to various embodiments a system for use in determining aposition of a first implantable member and planning and navigatingrelative to the first member for positioning a second member to interactwith the first member is disclosed. The system includes a trackingelement associated with the first member to assist in determining aposition of the first member. A first detector detects the trackingelement and a processor determines a position of the first memberdepending upon the detection of the first detector. A navigableinstrument is operable to move the second member relative to the firstmember; and a second detector detects the navigable instrument. Theprocessor is operable to determine a position of the second memberrelative to the first member in at least two planes. The processor isoperable to navigate the navigable instrument relative to the trackingelement for positioning of the second member relative to the firstmember.

According to various embodiments a method of percutaneous and/orminimally invasive implantation of a construct having at least a firstmember, a second member, and a third member is disclosed. The methodincludes positioning the first member and determining a position of thefirst member in a selected space. The method further includespositioning the second member relative to the first member anddetermining a position of the second member in the selected space. Also,navigating the third member relative to the first member and the secondmember may be performed. The navigation generally includes determining areal time optimal position of the third member in the selected space;and determining a real time position of the third member relative to atleast one of the first member and the second member.

According to various embodiments is also disclosed a method ofimplanting a construct of at least a first member, a second member, anda third member substantially percutaneously and/or minimally invasive.The method includes selecting a final orientation of at least one of thefirst member, the second member, and the third member relative to atleast one other of the first member, the second member, and the thirdmember. A determination of the position of the first member and thesecond member and displaying the position of each of the first memberand the second member is also performed. A characteristic of at leastone of the first member, the second member, and the third member isselected. Also, positioning with navigation at least one of the firstmember, the second member, and the third member relative to another ofat least one of the first member, the second member, and the thirdmember to achieve the selected final orientation.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an environmental view of a surgical navigation systemincluding an optional imaging system;

FIG. 2A is an ideal calibration image for the optional imaging system;

FIG. 2B is a non-ideal calibration image for the optional imagingsystem;

FIG. 3A is a construct according to an embodiment;

FIG. 3 b is a connector for the construct of FIG. 3 a according tovarious embodiments;

FIGS. 4A-4C are localization units according to various embodiments;

FIG. 5 is a navigable instrument to assist in positioning a connectoraccording to various embodiments;

FIG. 6 is a flow chart for a method of implanting and navigating aselected construct according to various embodiments;

FIG. 7A is a partial detailed view of a portion of a spine including aportion of a construct localization element affixed thereto;

FIG. 7B is a screen produced by the navigation system display indicatinga location of a first portion of a construct;

FIG. 8A is a partial detailed view of the spine including two portionsof a construct and a localization element affixed thereto;

FIG. 8B is a screen produced by a surgical navigation system includingtwo portions of the construct;

FIG. 9A is a display produced by the surgical navigation system forplanning the procedure;

FIG. 9B is a partial detailed view of a portion of the spine includingan element to assist in positioning a third portion of the construct;

FIG. 10A is a partial detailed view of the spine including threeportions of a construct including localization elements affixed theretoaccording to various embodiments;

FIG. 10B is a screen produced by the surgical navigation system toassist in positioning a third member of the construct;

FIG. 11A is a partial detailed view of the spine including a probe todetermine a contour of soft tissue surrounding the spine;

FIG. 11B is a screen produced by the surgical navigation systemincluding an optional image of the anatomical portions;

FIG. 12A is a partial detailed view of the spine including a connectorthat is navigable relative to other construct portions;

FIG. 12B is a virtual view of the connector interconnecting the variousportions of the construct and assisting in the navigation thereofaccording to various embodiments;

FIG. 13A is a partial detailed view of the spine including the constructassembled; and

FIG. 13B is a screen produced by the surgical navigation system toindicate completion of the procedure and optional confirmation using theoptional imaging system.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

The following description of various embodiments is merely exemplary innature and is in no way intended to limit the invention, itsapplication, or uses. Although the following description relatesgenerally to the placement of screws, such as pedicle screws, and amember or connector relative to the pedicle screws in a spinalprocedure, it will be understood that the apparatus and methods may beused for other procedures without departing from the scope of thepresent description and appended claims. For example, while pediclescrews may be implanted relative to a pedicle in a vertebrae, variousother screws may be implanted relative to other bone portions that mayalso be tracked and navigated using instruments and devices as disclosedherein. In addition, other implants, such as multi-component implantsthat require positioning of one component relative to another componentmay be implanted according to selected constructs using instruments andmethods similar to those described herein. These implants may includejoint implant, soft tissue implant, such as ligament implants, tendonimplants and spinal disc implants, and others.

Furthermore, the procedure may occur in any appropriate manner. Forexample, the procedure may be substantially open, or percutaneously orminimally invasively. Therefore, it will be understood that thedescription of the procedure is not intended to be limited to anyparticular form of a procedure. In addition a percutaneous and aminimally invasive procedure may be similar in regarding the small sizeof incisions, when compared to open procedures, to perform theprocedure. Generally, a percutaneous and/or minimally invasive procedureincludes a substantially small incision such that a portion of theoperative site is covered by dermis tissue and dermis tissue healingtime is reduced. Although an open procedure may also be percutaneous asoccurring generally through the skin and generally include a puncturewound.

With reference to FIG. 1, a surgical navigation system 20, which mayinclude any appropriate surgical navigation system, is illustrated. Forexample, the surgical navigation system 20 may include an opticalnavigation system, an electromagnetic navigation system, and acousticnavigation system, an ultrasound, or any other appropriate navigationsystem. Although the following discussion generally relates to the useof an optical navigation system, it will be understood that anyappropriate navigation system may be used and the optical navigationsystem is described merely as an example. Exemplary electromagneticnavigation systems are set out in U.S. Pat. No. 6,493,573, issued Dec.10, 2002, entitled “METHOD AND SYSTEM FOR NAVIGATING A CATHETER PROBE INTHE PRESENCE OF FIELD-INFLUENCING OBJECTS”; U.S. Pat. No. 5,592,939,issued Jan. 14, 1997, entitled “METHOD AND SYSTEM FOR NAVIGATING ACATHETER PROBE; U.S. Pat. No. 6,516,212, issued Feb. 4, 2003, entitled“THREE DIMENSIONAL MAPPING”; U.S. Pat. No. 6,522,907, issued Feb. 18,2003, entitled “SURGICAL NAVIGATION”; each of which is incorporatedherein by reference.

The surgical navigation system 20 generally includes an optical detector22 operably connected to a computer or processor 24 through anappropriate communication line 26. The detector 22 may also include aplurality of detector. Each of the plurality of detectors may be able todetect a different source, such as EM or optical. Therefore, thenavigation system 20 may be able to detect more than one trackingelement. The line 26 may be any appropriate line and may also be awireless connection. Therefore, the detector 22 may be positionedanywhere relative to the navigation computer 24 and communicatestherewith over the line 26. In addition, a monitor or display 28 may beprovided for a user to view, such as a surgeon 30. The monitor 28 may beany appropriate monitor and may also include a heads-up or head mounteddisplay. Nevertheless, it will be understood that the monitor 28 is ableto display an image produced by the computer 24 based upon a presetprogram or user input according to the teachings of the presentinvention.

The detector 22 may be operably located in any appropriate location suchthat the detector 22 is able to detect a tracking element 34 operablyconnected to a selected instrument 36. The detector 22 may also beoperable to detect any other appropriate tracking element. For example,the detector 22 may also be able to detect an optional dynamic trackingreference element 38. As discussed herein, however, the dynamic trackingelement 38 may not be necessary depending upon the selected parametersfor the surgical navigation system 20, the procedure being performed,user preference, and other appropriate considerations, further discussedherein. Nevertheless, if the dynamic reference tracking element 38 isselected to be used, the dynamic tracking reference 38 is generallyaffixed to a patient 40. The patient 40 is generally positioned on aselected platform or operating room (OR) table 42 for the procedure.

The tracking element 34 may include any appropriate tracking portion,that may depend on the various navigation systems. Various examplesinclude a tracking element selected from a group including anelectromagnetic tracking device, an optical tracking device, aconductive tracking device, a fiberoptic tracking device, an acoustictracking device, and combinations thereof. Similarly the detector may beformed to detected any of these tracking elements.

According to various embodiments an optical navigation system includesthe tracking element 34 that may include a selected number of reflectorsto reflect a light source or a light source, such as light emittingdiodes (LEDs). The detector 22 is able to detect the light emitted todetermine a position of the tracking element. In other systems, such aselectromagnetic systems, a coil may either transmit a field or detect afield to determine a location. The EM systems may help eliminate issuessuch as line of sight, such as when an opaque object blocks the path ofthe light from the tracking element 34.

During the procedure, the user 30 may use any appropriate input device44, element such as a foot pedal, to input a selected input into thenavigation computer 24. In addition, the monitor 28 may include a touchscreen, or other appropriate mechanisms such as a mouse or computerkeyboard as the input device 44. Nevertheless, the navigation system 20is generally able to navigate and determine a location of the trackingelements. In addition, an implant or secondary dynamic tracking element46 may also be provided. As discussed herein, the implant trackingelement 46 may be interconnected to a selected implant to determine alocation of the selected implant after it is implanted into the patient40. The implant tracking element 46 may also be used to track theimplant during any appropriate time such as during implantation, afterimplantation, or even before implantation for various reasons, such asdetermining an appropriate implantation position.

Generally, when the detector 22 is an optical detector 22 and thenavigation system 20 is an optical navigation system, the detector 22 isable to optically locate the various tracking elements 34, 38 and 46.The location of the tracking elements, may be referenced to anyappropriate reference. For example, the tracking elements may bereferenced to any position within the detector space, which is the spacethat is detectable by the detector 22. In addition, the trackingelements 34, 38 and 46 may be referenced to a patient space which isdefined by the space or area under which the procedure is beingperformed relative to the patient 40. In addition, the detector 22 maydetect, and the surgical navigation system 20 navigate, the varioustracking elements relative to images that may be acquired pre-, intra-,or post operatively. Nevertheless, as discussed herein, the detector 22is able to locate the various elements according to any appropriatespace for navigation by the navigation computer 24 for selected displayon the monitor 28. In addition the navigation computer 24 may navigatethe selected instruments relative to selected points, such as a positionof an implant, further discussed herein.

While the navigation system 20 is used to assemble a construct in animageless manner (i.e., no patient image is acquired before, during orafter the procedure), an optional image acquisition system 50 may alsobe used, if desired. The optional imaging device 50 may be used toacquire any appropriate pre-operative or real time images of the patient20. The optional imaging device 50 may be provided to obtainpre-operative imaging, such as magnetic resonance imaging (MRI),fluoroscopic, x-ray, and other appropriate or selected images. Ifpre-operative images are obtained, the pre-operative images may be usedto plan a selected procedure depending upon the data acquired from thepre-operative images. On the day of the procedure, the optional imagingdevice 50 may also be used to image the patient 40 for any selectedpurpose.

This image may be used for pre-operative planning, for scaling,morphing, translating or merging atlas maps or 3-D models, and to verifythat the construct has been assembled properly. For example, asdiscussed herein, the atlas map may also be scaled or morphed to theknown location, based upon the size and orientation of the implant, suchas the screw. Generally, the optional imaging device 50 may be selectedfrom any appropriate imaging device such as a computer aided topography(CT) imaging device or a fluoroscopic x-ray imaging device. If theoptional imaging device 50 is a CT device, the patient generally has aseries of CT scans taken on the area of interest for the selectedprocedure. In addition, if the optional imaging device 50 is thefluoroscopic device, a plurality or selected number of fluoroscopicx-ray images may also be taken. The pre-operative and intra-operative orimmediate operative images may then be merged or referenced dependingupon selected procedures. For example, the pre-operative andintra-operative images may include anatomical landmarks that may bereferenced by the navigation computer 24 and used to merge or registerone set of the images with another set of images or to register theimages to patient space as is known in the art. Various exemplary imagefusing systems include those set forth in U.S. patent application Ser.No. 10/644,680, filed Aug. 20, 2003 entitled “Method and Apparatus forPerforming 2D to 3D Registration”, which is incorporated herein byreference.

Other various image merging techniques may use fiducial markers that maybe referenced by both the pre and intra-operative images. In thisregard, distinct identifiable fiducial markers may be attached to thepatient 40 during the pre-operative scans, such as with the MRI. Thefiducial markers are generally identifiable in the MRI image dataset bya user or a selected computer. The fiducial markers are generally notremoved from the patient after the pre-operative images are obtained andthe data is captured such that they are also visible on the lateracquired images, such as with the CT or fluoroscopic image. By using thevarious common corresponding points of the two image data sets, thepre-operative and the intra-operative datasets can be identified thusallowing merging or registration of the images or registration betweenthe images and patient space. Other image or merging registrationtechniques include the use of surface contours or anatomical landmarkswhich can either be manually or automatically identified by theprocessor 24 to provide various merging and registration options, as isknown in the art.

As discussed above, the optional imaging device 50 may include afluoroscopic x-ray imaging device that may be used in a place of otherapproximate imaging devices, such as CT imaging. Similar registrationtechniques may be used to register the pre-acquired image dataset withthe later acquired image dataset such as from the fluoroscopic x-rayimaging system and with the patient space. The fluoroscopic x-rayimaging device, if used as the optional imaging device 50, may include afluoroscopic device 52, having an x-ray source 54, and x-ray receivingsection 56, and may include an optional calibration and tracking targetsand optional radiation sensors, such as those known in the art. Also atracking element 57 may be included on the optional imaging device 50,particularly on the receiving section 56. The calibration and trackingtarget generally includes calibration markers 58 (See FIGS. 2A-2B),further discussed herein. Such optional imaging systems may includethose described in U.S. Pat. No. 6,470,207, issued Oct. 22, 2002,entitled “Navigational Guidance Via Computer-Assisted FluoroscopicImaging” which is hereby incorporated by reference.

A fluoroscopic device controller 60 captures the x-ray images receivedat the receiving section 56 and stores the images for later use. Thefluoroscopic device controller 60 may also control the rotation of thefluoroscopic device 52. For example, the fluoroscopic device 52 may movein the direction of arrow A or rotate about the long axis of the patient40, allowing anterior or lateral views of the patient 40 to be imaged.Each of these movements involve rotation about a mechanical axis 62 ofthe fluoroscopic device 52. In this example, the long axis of thepatient 40 is substantially in line with the mechanical axis 62 of thefluoroscopic device 16. This enables the fluoroscopic device 52 to berotated relative to the patient 40, allowing images of the patient 40 tobe taken from multiple directions or about multiple planes. An exampleof a fluoroscopic device x-ray imaging device 50 is the “Series 9600Mobile Digital Imaging System,” from OEC Medical Systems, Inc., of SaltLake City, Utah. Other exemplary fluoroscopes include bi-planefluoroscopic systems, ceiling fluoroscopic systems, cath-labfluoroscopic systems, fixed fluoroscopic device systems, isocentricfluoroscopic device systems, 3D fluoroscopic systems, etc.

In operation, the imaging device 50 generates x-rays from the x-raysource 54 that propagate through the patient 40 and a calibration and/ortracking target 64, into the x-ray receiving section 56. The receivingsection 56 generates an image representing the intensities of thereceived x-rays. Typically, the receiving section 56 includes an imageintensifier that first converts the x-rays to visible light and a chargecoupled device (CCD) video camera that converts the visible light intodigital images. Receiving section 56 may also be a digital device thatconverts x-rays directly to digital images, thus potentially avoidingdistortion introduced by first converting to visible light. With thistype of digital, which is generally a flat panel device, the optionalcalibration and/or tracking target 64 and the calibration processdiscussed below may be eliminated. Also, the calibration process may beeliminated or not used depending on the type of therapy performed.Alternatively, the imaging device 50 may only take a single image withthe calibration and tracking target 64 in place. Thereafter, thecalibration and tracking target 64 may be removed from the line-of-sightof the imaging device 50. Again, it should be noted that the imagingdevice 50 is optional and may be utilized during the selected procedure,such as an implantation procedure, to merely confirm that the instrumenthas hit the desired target or that the construct has been assembledproperly.

Two dimensional fluoroscopic images taken by the imaging device 50 arecaptured and stored in the fluoroscopic device controller 60 and/ordirectly within the various navigation or viewing systems. Multipletwo-dimensional images taken by the imaging device 50 may also becaptured and assembled to provide a larger view or image of a wholeregion of a patient 40, as opposed to being directed to only a smallerportion or region of the patient 40. For example, multiple image data ofthe patient's spine may be appended together to provide a full view orcomplete set of image data of the spine that may be used at a selectedtime. These images are then forwarded from the fluoroscopic devicecontroller 60 to the controller, navigation computer or work station 24having the display 28 and the user interface 44. As an example, thenavigation computer 24 assembles the various images, but this may alsobe performed by the controller 60. The data set may be communicated overline 66 that may be a hard line or a wireless communication system. Thework station 24 provides facilities for displaying on the display 28,saving, digitally manipulating, or printing a hard copy of the receivedimages from both the imaging device 50 and from pre-operative scans,such as the preoperative MRI scans as discussed herein.

The user interface 44, as discussed above, may be a keyboard, mouse,touch pen, touch screen or other suitable device that allows a physicianor user to provide inputs to control the imaging device 50, via thefluoroscopic device controller 60, or adjust the display settings of thedisplay 28. The work station 24 may also direct the fluoroscopic devicecontroller 60 to adjust the rotational axis 62 of the fluoroscopicdevice 52 to obtain various two-dimensional images along differentplanes in order to generate representative two-dimensional andthree-dimensional images. When the x-ray source 54 generates the x-raysthat propagate to the x-ray receiving section 56, the radiation sensorssense the presence of radiation, which is forwarded to the fluoroscopicdevice controller 60, to identify whether or not the imaging device 50is actively imaging. Alternatively, a person or physician may manuallyindicate when the imaging device 50 is actively imaging or this functioncan be built into the x-ray source 54, x-ray receiving section 56, orthe control computer 60.

Fluoroscopic imaging devices 50 that do not include a digital receivingsection 56 generally require the optional calibration and/or trackingtarget 64. This is because the raw images generated by the receivingsection 56 tend to suffer from undesirable distortion caused by a numberof factors, including inherent image distortion in the image intensifierand external electromagnetic fields. An empty undistorted or ideal imageand an empty distorted image are shown in FIGS. 2A and 2B, respectively.The checkerboard shape, shown in FIG. 2A, represents the ideal image 64of the checkerboard arranged calibration markers 58. The image taken bythe receiving section 56, however, can suffer from distortion, asillustrated by the distorted calibration marker image 70, shown in FIG.2B.

Intrinsic calibration, which is the process of correcting imagedistortion in a received image and establishing the projectivetransformation for that image, involves placing the calibration markers58 in the path of the x-ray, where the calibration markers 58 are opaqueor semi-opaque to the x-rays. The calibration markers 58 are rigidlyarranged in pre-determined patterns in one or more planes in the path ofthe x-rays and are visible in the recorded images. Because the truerelative position of the calibration markers 58 in the recorded imagesare known, the c fluoroscopic device controller 60 or the work stationor computer 24 is able to calculate an amount of distortion at eachpixel in the image (where a pixel is a single point in the image).Accordingly, the computer or work station 24 can digitally compensatefor the distortion in the image and generate a distortion-free or atleast a distortion improved image 64 (see FIG. 2 a).

A more detailed explanation of exemplary methods for performingintrinsic calibration are described in the references: B. Schuele, etal., “Correction of Image Intensifier Distortion for Three-DimensionalReconstruction,” presented at SPIE Medical Imaging, San Diego, Calif.,1995; G. Champleboux, et al., “Accurate Calibration of Cameras and RangeImaging Sensors: the NPBS Method,” Proceedings of the IEEE InternationalConference on Robotics and Automation, Nice, France, May, 1992; and U.S.Pat. No. 6,118,845, entitled “System And Methods For The Reduction AndElimination Of Image Artifacts In The Calibration Of X-Ray Imagers,”issued Sep. 12, 2000, the contents of which are each hereby incorporatedby reference.

While a fluoroscopic imaging device 50 is shown in FIG. 1, any otheralternative 2D, 3D or 4D imaging modality, as already discussed herein,may also be used for preoperative, intraoperative, and postoperativeimaging. For example, any 2D, 3D or 4D imaging device, such asfluoroscopic, fluoroscopic isocentric, bi-plane fluoroscopy, ultrasound,computed tomography (CT), multi-slice computed tomography (MSCT),magnetic resonance imaging (MRI), high frequency ultrasound (HIFU),positron emission tomography (PET), optical coherence tomography (OCT),intra-vascular ultrasound (IVUS), ultrasound, intra-operative CT or MRImay also be used to acquire 2D, 3D or 4D pre-operative or real-timeimages or image data of the patient 40, further discussed herein. Theimages may also be obtained and displayed in two, three or fourdimensions. In more advanced forms, four-dimensional surface renderingof the body may also be achieved by incorporating data from an atlas mapor from pre-operative image data captured by MRI, CT, MSCT, HIFU, OCT,PET, etc. A more detailed discussion on optical coherence tomography(OCT), is set forth in U.S. Pat. No. 5,740,808, issued Apr. 21, 1998,entitled “Systems And Methods For Guilding Diagnostic Or TherapeuticDevices In Interior Tissue Regions” which is hereby incorporated byreference.

Regarding the use of atlas mapping, atlas maps may be utilized duringthe preplanning stage to locate target sites within the spine, or otherselected anatomical region, of the patient 40. In this regard, knownanatomical atlas maps may be used and scaled to the particular patient40 or patient specific atlas maps may also be utilized that are updatedover time. In this regard, over multiple procedures, enhancements andrefinements in the location of certain desired sites within the anatomymay be updated as these procedures are performed, thus providing anatlas map that is updated with each surgical procedure to provide moreprecise mapping by performing more procedures and gathering additionaldata. These atlas or patient specific atlas maps may then besuperimposed onto optional preacquired images to identify relevantlocations of interest. Alternatively, only the atlas models may be usedto provide a true imageless system with the advantage of providing thesurgeon an anatomical reference during the procedure and without theneed to capture images of the patient, further discussed herein.

Image datasets from hybrid modalities, such as positron emissiontomography (PET) combined with CT, or single photon emission computertomography (SPECT) combined with CT, may also provide functional imagedata superimposed onto anatomical data to be used to confidently reachtarget sights within the areas of interest. It should further be notedthat the fluoroscopic imaging device 50, as shown in FIG. 1, provides avirtual bi-plane image using a single-head C-arm fluoroscope 50 bysimply rotating the C-arm 52 about at least two planes, which could beorthogonal planes to generate two-dimensional images that can beconverted to three-dimensional volumetric images. By acquiring images inmore than one plane, an icon representing the location of an instrumentor lead, introduced and advanced in the patient 40, may be superimposedin more than one view on display 28 allowing simulated bi-plane or evenmulti-plane views, including two and three-dimensional views, ifdesired.

With reference to FIG. 3A and additional reference to FIG. 1, aconstruct 80 that may be implanted in an imageless manner in a spine torigidly fix relative vertebrae is shown. The construct 80 generallyincludes a plurality of first members or pedicle screws 82 that may beimplanted into a selected vertebrae as is known in the art. The firstmembers, however, may be a fastener of any appropriate type. The screw82 generally includes a head portion 84 and a threaded portion 86. Thethreaded portion 86 is generally adapted to threadably engage a selectedboney portion and be held therein. The head portion 84 is formed toremovably receive a localization element, further described herein andmay also be formed to operably engage a connector 88. In this regard thescrew 82 includes or defines a slot 90 that is operable to slidablyreceive the connector 88. Also, the head portion 84 may be moveable orpivotable relative to the threaded portion 86. Thus, the screw 82 mayalso be a multi-axis screw. The screw 82 may also define a cannula 91through the screw. Therefore, the screw 82 may be positioned over aguide wire or K-wire that has fitted into a selected position, such aspedicle to assist in positioning the screw 82 thereto. Nevertheless, thescrew 82 need not be cannulated and need not include the cannula 91,therefore, the cannula 91 is optional.

The connector 88 is selected from a plurality of connectors havingvarious characteristics, for example a first connector 92, a secondconnector 94, and a third connector 96. The first connector 92 include aradius or arc B of any appropriate size. In addition, the connector 92includes a selected length, which also may be varied or numerous.Likewise, the second connector 94 defines a second arc C while the thirdconnector 96 defines a third arc D. Each of the connectors, 92, 94, 96may define different or same arcs or radii. In addition, each may definea substantially equal length or different lengths and may be provided asa kit with or without the screw 82. Nevertheless, the connector 88 inconjunction with the screws 82 form the construct elements from whichthe construct 80 may form a spinal implant. It will be understood thatthe type and number of elements is merely exemplary and any appropriatemembers may be used to form the construct 80.

In addition, the connectors 88 may or may not be rigid members thatrigidly interconnect the screws 82. Regardless, the connector 88 may beselectable in size, shape, orientation, arc, length, and any otherappropriate dimension relative to a selected procedure. Also, theconnector 88 may be a substantially drivable or steerable element 98.With reference to FIG. 3B, steerable element 98 includes a cover orballoon 100 that may be filled with a selected compound, such as acarbon or bone matrix that may set to form a substantially rigid rod.The steerable connector 98 may also include a substantially steerable orguidable portion 102 that allows the steerable connector 98 to be movedbetween relative directions. The guidable portion 102 may be selectedfrom but not intended to be a limiting example, from a guided stylet orK-wire that is used to position the balloon 100 in the selectedposition. The steering member 102 may steer the steerable connector 98as an assembly and once positioned in the selected position thehardenable or curable material may be used to fill the balloon 100 andallowed to cure to form a substantially rigid connector. Therefore, theconnector 88 need not be predetermined, but may be selected during theprocedure. Also, the connector 88 need not be rigid nor include aballoon to be filled with a matrix, but may be at least partiallydeformable such that it may be placed under tension. For example, theconnector 88 may be formed as a cord or cable that includes a selectedstiffness but may be deflected to provide a selected tension to aselected component, such as an anatomical portion. As described herein,the connector may be navigated to a selected location. Therefore, theconnector 88 may also include a tracking element to be detected by thedetector 22.

With continuing reference to FIG. 3A and additional reference to FIGS.4A through 4C, a localization member may be any appropriate localizationmember, for example a first localization member 104, a secondlocalization member 106, and a third localization member 108. Eachlocalization member includes a tracking element 110, 112, and 114,respectively. Each of the tracking elements 110, 112, and 114 may bedetected by the optical detector 22, as described herein. In addition,each of the localization members 104, 106 and 108 may include a cannula104′, 106′ and 108′, respectively. The cannula 104′, 106′ and 108′ maygenerally be substantially aligned with the cannula 91 formed in thescrew 82, if one is provided. In addition, each of the localizationelements 104, 106, and 108 need not be cannulated and are onlyoptionally cannulated to assist in positioning the localization elements104, 106, and 108 relative to the respective screw 82 and over a guidewire, if used.

With reference to FIG. 4A, the localizer 104 includes the trackingelement 110 that is operably affixed to an extender or positioningelement 116. The extender 116 generally interconnects with the screw 82through any appropriate means. For example, the extender 116 may includea depressible member 118 that operates an internal mechanism to engageand disengage the head 84 of the screw 82. Therefore, the extender 116may be quickly engaged and disengaged percutaneously from the screw 82at a selected time.

Also, the extender 116 may be keyed relative to a selected shape of thehead 84 of the screw 82 or may simply be positioned on the screw 82 toprovide a position thereof. If the extender 116 is generally keyed to aposition of the screw 82 or a portion of the screw 82, the localizationunit 104, or any of the localization elements, may substantially onlyengage the screw 82 in one selected position and may be used todetermine a position, an orientation, and rotational (i.e., six degreeof freedom) information. This may assist in determining an orientationof the threaded portion 86 relative to the head 84 when the head 84 ismoveable relative to the threaded portion 86. Otherwise, thelocalization units, 104, 106, and 108 may be selected to provide only athree-dimensional location, generally including the coordinates X, Y andZ, and rotational position of the screw. Generally, the localizationunits, 104, 106, and 108 are able to determine the center of rotation ofthe screw such that the known position of the tracking element 110 mayallow for a determination of the orientation of the screw.

Alternatively, a multi access screw may include a head or a portion ofthe head 84 that may be moved randomly relative to a threaded portion ora body 86 of the screw 82. Therefore, rather than having an extenderthat is keyed to a specific or selected screw, the extender may operablyengage the multi access screw to fix the head in a selected position.Therefore, the extender may engage the multi-access screw in a generallyknown manner to fix the screw in a selected orientation. The extenderengages the screw and holds it in the selected orientation such that theorientation of the screw is known due to the attachment of the extender.This allows a determination of an orientation of the screw because theextender has locked the screw in the selected position.

The extender 116 includes a known length or dimension. Similarly, theposition of a plurality of tracking points 120 and 122 and 124 aregenerally known relative to the dimension of the extension 116.Therefore, the detector 22 may detect the tracking points 120, 122, 124and determine the position of the screw 82 using the information, suchas length of the extender 116 stored in the computer 24. Again, thetracking points 120, 122, 124 may be LEDs or reflectors for the opticaldetector 22, as is known in the art. In the alternative, when thenavigation system is an electromagnetic type of system EM coils may beused. In addition, the screw 82 may internally include the selectedtracking points, such as EM coils. Therefore, the screws 82 may bedetected without attaching the localization element 104 to the screw. Itwill be understood that any appropriate number of screws may use EMcoils as the tracking device or localization elements, thus thelocalization elements 104, 106, and 108 may not be necessary.

With reference to FIG. 4B, the second localization unit 106 may includean extender 126 that includes a second selected length. Attached to theextender 126 is a tracking element 112 that includes three differenttracking points 128, 130 and 132. Again, the extender 126 is generallyinterconnected with a screw 82 at a selected time. Again, quick releaseor attachment levers 134 allow for easy and selectable connection to thescrew 82. Again, the extender 126 may be keyed or simply connectable tothe head 84 of the screw 82. In addition, the third localization element108, with reference to FIG. 4C, includes an extender 136 may include atracking element 114 that includes tracking points 138, 140, 142. Again,detachable levers may be provided to interconnect the extender 136 withthe screw 82. Also, the extender 136 may include a length different fromthe extenders 116, 126 and the tracking element 114 may includedimensions or shapes different from the tracking elements 110 and 112.

The navigation computer 24 generally includes a database of the distinctshape of each of the various localization elements 104, 106, and 108that may be provided for use with the construct 80. Therefore, theextender 116 may be chosen and the use of the extender 116 is selectedon the navigation computer 24. In addition, the position of the extender116 is also noted by the tracking computer 24, generally through aninput provided by a user, which may be the physician or an assistant tothe physician, such that the detector 22 is able to detect the trackingelement 110 and the detector 22 is able to transmit the location of thetracking element 110 to the computer 24. The computer 24 is then able todetermine the position of the screw head 84 due to the known length ofthe extender 116, the orientation and size of the tracking element 110,and therefore display on the monitor 28 an icon representing theposition of the screw 82.

Similarly, if the extenders 126 and 136 are used, the pre-known orpre-programmed sizes, orientation, and dimensions of the extenders 126,136 and the relative tracking elements 112, and 114 are also known suchthat there inputted attachments to a selected screw can be used by thecomputer 24 to display on the monitor 28 the position of the otherscrews 82. It will also be understood that a plurality of each of thelocalization elements 104, 106, and 108 may be used in a selectedprocedure and programmed into the computer 24 such that the computer 24is able to know the distinct location of each.

In addition, the various configurations of the tracking elements 110,112, 114 may be used by the computer 24 to identify each of therespective localization elements, 104, 106, and 108. Therefore, thetracking element 110 may include a geometry different from that of thetracking element 112 such that the computer 24 is able to distinguishthe location of each of the localization elements 104, 106, 108. Thecomputer 24 may be preprogrammed with the size of each of the specificlocalization units 104, 106, 108 depending upon the geometry of thetracking elements such that the computer 24 is able to determine thepresence of any of the programmed localization elements 104, 106, 108and determine the position of the screw 82 relative thereto. It will beunderstood that although the tracking element 110, 112, 114 is displacedfrom the screw 82, the position of the screw 82 is known because theextension portion 116, 126, 136 is substantially rigid and does notchange over the course of the procedure.

As noted above an EM based navigation system may also be used as opposedto an optical based system. In an exemplary EM based system coils may bepositioned in the implanted elements, such as a pedicle screw. The coilsembedded in the screw can then be detected, by transmitting or detectingan EM field, to determine the location of the screw. Therefore, althoughthe following discussion relates to the use of an optical system it willbe understood that an EM navigation system, or any appropriatenavigation system, may be used.

Reference to the dynamic reference frame 38 if selected, or reference tothe tracking element of any of the selected localization members 104,106, 108, may be used by the navigational computer 24 to determine thelocation of the instrument 36 or any selected element relative to theselected reference. Therefore, any selected reference point may be usedto navigate the instrument 36 or any appropriate selected member, suchas the connector 88. Although the following discussion relates toreferencing a selected implant and the localization member affixedthereto, it will understood that reference may be made to any selectedtracking element or selected portion.

With reference to FIG. 5, the instrument 36 may be any appropriateinstrument, such as an instrument that is operable to engage one of theconnectors 88, such as the connector 92. The instrument 36 also includesthe tracking element 34, which includes a plurality of tracking points,such as tracking points 146, 148, 150, and 152. The tracking element 34is detectable by the detector 22 so that the navigation computer 24 isable to determine the location of the instrument 36 and hence thelocation of the connector 92.

The instrument 36 engages the connector rod 92, such that the instrument36 is able to move the distal end 92 a of the connector 92 in a selectedmanner. A proximal end 92 b of the connector 92 is removably engaged toa portion of the instrument 36. The connection between the rod 92 andthe instrument 36 may be any appropriate connection. Nevertheless, theinstrument 36 may be used to move the rod 92 during the procedure.

The location of the distal end 92 a may be determined by the location ofthe instrument 36 because the rod 92 is generally rigid. Therefore, theposition of the rod 92, and particularly, the position of the distal tip92 a may be determined relative to the tracking element 34, such thatmovement of the distal tip 92 a can be determined by a movement orlocation of the tracking element 34.

Nevertheless, as discussed above, the connector 88 need not necessarilybe a rigid connector. When the connector 88 is substantially not a rigidconnector, a different tracking element may be positioned relative tothe connector 88. For example, the connector 88 may include an EM coilor multiple coils that are able to be tracked by the tracking apparatus20 if the tracking apparatus includes an EM tracking system. Therefore,the connector 88 may be tracked using the EM sensor coils to determinethe position of the connector 88. Alternatively, the connector 88 may begenerally steerable such that a user may steer the connector 88 along aselected path. In this instance, the computer may be able to inputtedwith the distance the connector 88 has traveled, the number of turns,the severity of the turns, the distance traveled along a selected turn,such that a distal end point of the connector 88 may be determinedknowing each of these known distances and turns. Again, it will beunderstood that these are merely exemplary of different ways of trackingthe connector element 88 during a procedure. Therefore, it will beunderstood that the present disclosure and the appended claims are notso limited by such examples.

Various instruments and apparatii have been above disclosed. Generally,the localization system or navigation system 20 is able to localize theconstruct portions 80 implanted in an anatomy and also able to determinethe location and assist in navigation of the connector 88 during animageless procedure. Although the instrument 36, the construct portions80, and the localization and navigation apparatii 20 may differ, amethod of using the various elements will now be described.

With reference to FIG. 6, a general method for performing a imagelessprocedure to implant a construct is illustrated in the flow chart 146.The method or program 146 generally begins at a start block 148. At thebeginning of the procedure, a first member of the construct is implantedin block 150. As discussed below, the first member may include a firstpedicle screw that may or may not be cannulated. Next, the position ofthe first member is determined in block 152. As discussed above, andfurther herein, the localization element 104 may be used to determinethe first position. Nevertheless, and as discussed further herein,various other techniques may be used to determine the position of thefirst member. For example, the instrument 36 may also be a probe thatmay simply contact the screw to identify the corresponding location.After the position of the first member is determined, the position maybe saved in block 154. Generally, the position of the first member issaved in block 154 and can be used as the reference for determiningrelative locations of other members, after the implant. Again, theposition may include x, y, z positions and/or orientations.

After the position of the first member is saved in block 154, anoptional determination of a coordinate system may be determined in block155. Although the determination of the coordinate system may occur aftersaving the position of the first member in block 154, the determinationof the coordinate system may occur at any time. For example, acoordinate system relative to the user 30, the patient 40 or anyappropriate coordinate system may be determined. This determination mayoccur before positioning the first member or after positioning anyappropriate number of members. Generally the coordinate system assiststhe user 30 in determining an orientation of the members relative to thepatient 40. Also, the coordinate system may assist in orienting an atlasor 3-D model on the display 28 relative to the members of the construct,as illustrated herein. The coordinate system, therefore, may include anyappropriate number of coordinates, such as X, Y or X, Y, Z.

Generally, the coordinate system may be determined by sensing a locationof a position of the patient 40 relative to the first implant. Asdescribed herein, this may be done by determining a position of thefirst member in block 152 or may be done as a separate step. Forexample, the user may touch a relative superior portion of the patient40 and input the position into the navigation computer 24 followed bytouching a relative inferior, lateral, medial, or any appropriateposition. Alternatively, the coordinate system may be determined bycontacting several portions of the anatomy of interest (i.e., vertebra)and using surface recognition software to identify the orientation ofthe region of interest. The coordinate system may be determined in block155 in any appropriate manner. In addition, as discussed herein, thecoordinate system may also be fine tuned or determined when determininga location of the selected soft tissue in block 180. Nevertheless, itwill be understood that determining coordinate system is not necessaryto the method 146 and is merely optional.

As discussed above, the field reference or dynamic reference frame 38may be positioned to determine the relative location of all elementsrelative to the dynamic reference frame 38. The dynamic reference frame38 may be used for procedures where the patient may move during theprocedure. in such a situation use of the dynamic reference frame 38 mayincrease accuracy. For lower spinal fusion, however, movement of thepatient is at best minimal and the dynamic reference frame 38 isgenerally not required. Nevertheless, in addition to and alternative tothe field localizer 38, the position of the first member may be saved asa “true” location or reference. This may be especially the case when theposition into which the first member is fixed is substantially immobile.Therefore, all other points that are formed relative to the position ofthe first member can be known relative to the position of the firstmember and various determinations may be based thereupon. In additionthe construct may be assembled only knowing the relative location of theimplanted members. In this case the navigation computer may determinethe location of each element in real time.

With continuing reference to FIG. 6 and the method of 146, placing asecond member of the construct is performed in block 156. As discussedabove, the second member may include a second pedicle screw positionedin a vertebra. After the second member is positioned, determining theposition of the second member is performed in block 158. Also asdiscussed above, determining the position of the second member mayinclude positioning the second localization element 106 relative to thesecond member. Nevertheless, also as discussed above, various othertechniques may be used for determining the position of the second memberor the first member as discussed in block 152. Nevertheless, theposition of the second member may be determined through any appropriatemethod. For example a navigable needle may be used to touch or indicatea location of the second member. The position of the second memberrelative to the first member is saved in block 160.

The position of the second member may also be a “true” position. Thatis, both the position of the first member and the position of the secondmember may be generally determined and known by the computer 24. In thiscase a localization element would be attached to each member during theprocedure and would be essentially act as a dynamic reference frame foreach member. Generally, the positions of the first member and the secondmember saved in blocks 154 and 160 respectively, are saved in thenavigation computer 24 for display on the monitor 28. In addition, thenavigation computer 24 is able to use these locations for various otherportions of the procedure.

After the position of the first member and the second member are saved,the computer 24 may assist or be used to determine placement of variousother elements of the construct. An alignment of the anatomy, relativeto the construct and to be formed by the construct, can be selected inthe first plane in block 162. Similarly, an alignment in the secondplane may be selected in block 164, again for use with or to be formedby the construct. The alignment in both the first and the second planesare selected in blocks 162 and 164, respectively, may also be suggestedby the computer 24. These planes are generally positioned orthogonal toone another, but may be positioned at any appropriate angle relative toone another.

The computer 24 may suggest an alignment to be produced in the anatomybased upon generally known portions of the construct, as describedherein. For example, as described above, the construct may include aplurality of connectors 88 each including a different characteristic.Therefore, the computer 24 may assist in suggesting a position of athird member to assist in forming an alignment that would allow forimplantation of a selected or known connector. In addition, it will beunderstood, that any number of planes or alignments may be suggested orselected. Simply the inclusion of two planes for selection is forclarity of the following discussion, but will be understood that anyappropriate alignment, even outside of a selected plane, may bedetermined and selected.

After the selected alignments are chosen in blocks 162 and 164, alocation of a third member may be determined in block 166. Generally,the location of the third member determined in block 166 may allow forachieving the selected alignments in the first plane and second planesselected in blocks 162 and 164. Again a user or the computer 24 mayselect the location of the third member to achieve the selectedalignment.

Real time navigation may be provided for positioning the third member inthe determined location in block 168. Although various techniques may beused for providing the real time navigation, a navigated needle or probe236 or 246 (FIGS. 9B and 11A) may be used to ensure that a selectedtrajectory, to achieve the determined location of the third member inblock 166 is assured. In addition, the navigated needle may act as aguiding member such that the screw may be guided into the anatomy usingthe navigated needle to achieve the determined location in block 166.

During the positioning of the third member, the third member can beguided to align the third member according to a characteristic of afourth member. For example, as discussed herein, if the third member isa screw, the third screw may be positioned distally and proximally toensure that the fourth member, that may include the connector 88, may bepositioned relative to each of the three members in a selectedorientation.

An indication of the length and other characteristics, such as theradius, of a fourth member may be indicated in block 172. The indicationmay occur at any appropriate time, such as once the third member hasbeen positioned and guided to ensure that the appropriate orientationand location is achieved, That is, the position of each of the threemembers is known such that a length between the three members and aradius achievable with the positioned members, or other characteristicsdefined by the three members, may be known and displayed on the monitor28.

The user may select a fourth member based upon the shown characteristic.The determination of the fourth member is generally achieved bypositioning the third member in a selected location. Nevertheless, itwill be understood that any appropriate number of members may beprovided. The positioning of generally three members and theinterconnection of the three members with the fourth member is simplyexemplary. For example, only two members may be positioned and a thirdmember interconnect those two members. Alternatively, any number ofmembers may be fixed in a selected portion of the anatomy and aconnector used to interconnect each of the plurality of members.Therefore, only providing three members and interconnecting them withthe fourth member is not intended to limit the disclosure or the scopeof the appended claims.

After the appropriate fourth member characteristic or fourth member hasbeen chosen, the user may accept the plan including the choice of thefourth member. The user may Decline in block 176 the plan as outlined inblock 174. In this case, the position of the third member can be furtherguided in block 170. The guiding and the positioning of the third membermay require movement of the third member such that a different locationmay be achieved. This different location may then be used to determine anew appropriate characteristic for the fourth member in block 172 inproviding a new plan outlined in block 174. Once the user agrees withthe plan as determined in block 174, the user may Accept in block 178the plan outlined in block 174. After the plan is accepted, other pointsfor navigation may be determined to assist in the navigation of theprocedure or the procedure may proceed only using those points alreadydetermined and the information generally available to the user.

After accepting the plan various other characteristics, relative to theanatomy, for implantation may be determined. For example, a location ofthe soft tissue surrounding the implantation site may be determined inblock 180 and a location of entry may be determined in block 182.Although it will be understood that the determination of a location orcontour of the soft tissue in block 180 and the location of an entrypoint termination in block 182 is not necessary, such determinations maybe useful in the implantation procedure.

Determining a location of the soft tissue relative to the implantationarea may include dragging an instrument over a surface or determining aplurality of points of a surface of the soft tissue surrounding theimplant area, such as the spine, relative to the first, second, andthird members, using a selected probe. In an example, the probe 246(FIG. 11A) may be interconnected with the navigation computer 24 or maybe detected with a detector 22 such that a contour of the soft tissuerelative to the implantation area of the first, second, and thirdmembers may be determined. The contour determination may be performed byproviding a probe that may be touched to the skins surface in aplurality of points to determine a contour of the soft tissue. Once thecontour of the soft tissue is determined, a specific location for entryof the fourth member may be determined and selected in block 182.

The contour of the soft tissue may be determined such that thenavigation computer 24 may assist in selecting an entry point for thefourth member to assist in implanting the fourth member relative to thefirst, second, and third members, or any appropriate number of members.As described herein, this may assist the user in insuring asubstantially easy implantation in alignment of the first, second, andthird members during the implantation of the fourth member.

Also, the location of other appropriate soft tissues, such as tendons orligaments, may be known and used to assist in providing information tothe navigation computer to balance the sheer forces of the constructrelative to the soft tissue after the implantation of the construct.Therefore, the navigation computer 24, or a user, may determine or inputa location of the soft tissue, position of the soft tissue, or positionof a soft tissue implant, to provide a selected tension, stress, orother forces, on the construct. For example, it may be desirable tobalance the forces among each of the portions of the construct, andpositioning soft tissue or knowing the position of the soft tissue mayassist in such balancing.

Because of the determination of the location of the selected soft tissuein block 180 and the determination of a location of entry in block 182is not necessary these blocks may simply be skipped and after acceptingthe plan in block 178, the fourth member may be attached to a selectedinstrument in block 184. Alternatively, the selected member may beattached to the instrument after or relative to determining location ofthe soft tissue in block 180 and determining a location of entry inblock 182. Nevertheless, the fourth member, which may include theconnector 88, is generally affixed to the instrument, as illustrated inFIG. 5.

The instrument 36 may be any appropriate instrument and is generallyillustrated to be a clamp member that may selectively engage theconnector 92 for the procedure. Calibration and verification may occurof the fourth member relative to the instrument in block 186. Thisallows the navigation computer 24 to be able to verify or determine aposition of the connector, such as the distal end 92 a, relative tomovement of the instrument 36. Once the calibration and determination iscompleted, the navigation computer 24 may use the information providedby the detector 22 to determine position of the end distal portion 92 aor the connector 92 due to movements of the instrument 36 in theinterconnected location elements 230.

Once the calibration and verification of the fourth member relative tothe instrument is performed in block 186 the tip, such as the distal end92 a of the connector 92, can be localized in block 188. Generally, theposition of the tip may be localized relative to a selected path of thefourth member. This may be done in any appropriate manner, such as thatdescribed herein, but generally may be schematically indicated as acrosshair on the monitor 28 relative to a selected path which may beillustrated as a circle.

Once the tip of the fourth member has been localized in block 188movement of the fourth member may be tracked and guided in block 190relative to the plan determined in block 174 and accepted in block 178.Generally, although various techniques and illustrations may be used,the movement of the fourth member may be tracked due to the fixation ofthe fourth member relative to the instrument 36 which includes thelocalization element 230 such that the movement of the instrument 36 maybe used to determine a position of the fourth member. The movement ofthe fourth member may therefore be illustrated as the movement of acrosshair on the monitor 28 and illustrated relative to a circle whichmay dynamically indicate the planned position of the tip of the fourthmember relative to the actual position of the tip of the fourth member.

As the fourth member is moved relative to the first, second, and thirdmembers, such as during the implantation procedure, a real-timeindication of the progress of the fourth member relative to the plan maybe illustrated in block 192. In this way, a user may determine theprogress of the fourth member to understand the position of the fourthmember relative to the first, second, and the third members and otherportions of the anatomy. In addition, the indication of the progress mayillustrate the position of the member relative to the anatomy to allowfor any adjustment that may be necessary due to selected anatomicalportions, peculiarities of the anatomy, the particular area into whichthe fourth member is being moved, or other various considerations. Inaddition, the progress of the fourth member may be used to determine anend point to the fourth member has reached a selected point in block194.

Generally, the tip of the fourth member, including the distal end 92 a,may selectively reach the second member, which may be an end point ofthe implantation procedure. Nevertheless, the determination of thefourth member reaching the selected point may indicate that theprocedure has achieved a selected result and the procedure may generallyend in block 196. Although it will be understood that a surgicalprocedure may not simply be completed with the implantation of a fourthmember, and it may include various other procedures such as stitches toclose any incisions, the application of various medications andantibiotics, or other appropriate applications, the navigation of thefourth element to the selected end point may generally end thenavigation procedure.

It will also be understood that the method 146 need not simply belimited to the navigation of the construct 80 relative to a selectedanatomy. For example, a construct such as a multi-element acetabularimplant, femoral implant, humeral implants, tibial implant, bone plate,combinations thereof, or any appropriate implant may be guided using themethod 146. Generally, any selected first member may be implanted and asecond member may be imagelessly guided relative to the other members toachieve a selected result.

In addition, it will be understood that the method 146 need notnecessarily be limited to use for implantation relative to an anatomy.For example, the method 146 may be used to position a member in anyvisually restrictive location, such as building a wing element of anairplane, an internal engine, or any position which may limit theoptical visualization by a user of the location of a selected member. Inaddition, the method 146 may be used to position a first member relativeto a second member from locations that are known due to pre-saved ordetected location such that members may be moved relative to oneanother.

As an exemplary use of the method 146 for implanting a construct, suchas a spinal implant, is included in the following description but isintended only to be an exemplary use of the method 146. Therefore, itwill be understood that the method 146 may be used to implant anyappropriate implant, but may also be used to implant the construct 80.

Also, as discussed herein, the procedure is performed substantiallywithout capturing patient images, regardless of when acquired, with anyimaging device, such as the optional imaging device 50. The navigationsystem 20 may navigate the various portions, including the instrument36, relative to known points, such as the position of the first screw206 or the dynamic reference frame 38. Generally, the positions of thesewould be shown as icons alone on the display 28. Nevertheless, anunmorphed atlas map of the spine, or any other appropriate portion, mayalso be superimposed over the icons or vice versa of the implantedportions for any appropriate reason. Regardless of the icons on thedisplay 28, registration of images is not required for appropriateperformance of the procedure. As discussed herein, patient images may beacquired for confirmation of the proper placement of the construct, orany other appropriate reason, but images of the patient, such as thosethat may be acquired with the optional imaging system 50, are notrequired.

With reference to FIG. 7A, an exemplary construct 80 may be implantedrelative to a selected portion of a spine 200 using the method of FIG.6. The spine 200 is generally surrounded by soft tissue, such as adermis 202 and other muscles and tendons, not particularly illustrated.Nevertheless, it will be understood that an incision 204 is generallyformed through the soft tissue, including the dermis 202 to obtainpercutaneous and/or minimally invasive access to the spine 200. That isthe procedure is generally not open and includes little or no directviewing of the spine. This allows the procedure to be minimally invasiveand/or percutaneous to reduce stress to the patient and healing time.The following description may reference the method 146 illustrated inFIG. 6 generally and specifically to the processes occurring for theexemplary implant of the construct 80.

It will be understood that the following method may be used inconjunction with a patient image of the spine, such as one acquired withthe optional imaging system 50, to be performed with images.Nevertheless, it will be understood that the process and the method isgenerally performed without use of any anatomical patient images suchthat the method may be performed substantially imageless or simplyinclude an atlas model. As exemplary illustrated herein, the monitor 28may display a patient image, that may be preacquired or acquiredintraoperatively. Similarly, an atlas model may be displayed on themonitor 28 that may be morphed relative to known sizes and orientationsof the spine 200 on which the procedure is performed. Typically,however, no preacquired images are obtained and the monitor 28 maysimply display icons representing the positions of the various members,including the screws 82, and other selected points, thereby eliminatingthe need for registration and of capturing patient images.

With reference to FIG. 6 and FIG. 7A, the process is generally startedin block 148. As discussed above, the incision 204 and optionalpreacquired images may be obtained prior to or at the start block 148.After the incision 204 is formed, a first screw 206, is positioned in apredetermined position, such as a first vertebrae 208. It will beunderstood that the first screw 206 may be positioned in any appropriatelocation.

Nevertheless, once the first screw 206 is positioned in the firstvertebrae 208 the position of the first screw 206 can be determined,such as determining the position of the first member in block 152. Theposition of the first screw 206 can be determined by positioning thefirst localization element 104 relative to the first screw 206. Asdiscussed above, the localization member 104 may include the extender116 that is able to selectively engage a portion of the first screw 206.In addition, the localization unit 104 includes the tracking element 110that includes portions that may be detected by the detector 22, such asdetectable portions 120, 122 and 124. Therefore, after the first screw206 is inserted into the vertebrae 208, the localization unit 104 may beaffixed thereto. The localization unit 104 is used to determine thelocation of the first screw 206. The detector 22 detects the location ofthe tracking element 110, such that the detected location can betransmitted to the navigation computer 24 and illustrated on the monitor28, via an icon representing the first screw 206.

The localization element 104 may be able to provide any selectedinformation. For example, the localization element 104 may be keyed to aselected shape of the first screw 206, such that the localizationelement 104 may engage the first screw 206 in substantially only onemanner. In this way, the trajectory, rotational position, and locationof the first screw 206 may be determined with six degrees of freedominformation. In addition the axis of the screw head 86 may be determinedif the screw 206 is a multi-axis screw. Although this is not required,it may be selected to determine this information depending upon theimplant being implanted, such as the construct 80 where the connector 88is selected to engage the screws in a selected manner.

In addition, the localization element 104 may include any appropriatelocalization portion different from the tracking element 110. Forexample, an optical based tracking element may be included as a trackingelement 110 or selected coils may be positioned relative to the trackingelement 110, such that an EM system may be used to determine thelocation of the first screw 206. Also, the first screw 206 may includeinternally contained elements, such as coils, that are able to belocated using an EM location system. Therefore, it will be understoodthat the localization elements, 104, 106, and 108 are only exemplaryapparatuses to determine the location of the first screw 206. Moreover,by having localization element 104 continuously affixed to screw 206, nodynamic reference frame 38 is required since any movement of thevertebrae will be detected by the detector 22, via localization element104. Alternatively, a navigatable needle or probe 246 (FIG. 11A) maysimply be used to contact the screw 200 to determine its location. Inwhich case, a dynamic reference frame 38 attached to the vertebra ofinterest may be helpful.

After the location of the first screw is determined, such as in block152 the location of the first screw 206 is saved in the navigationcomputer 24, such as included in block 154 where the position to thefirst member is saved. Therefore, the position of the first screw may beillustrated on the monitor 28. With reference to FIG. 7B, the monitor 28may be any appropriate monitor, such as a cathode ray tube, liquidcrystal display, plasma display, or a goggle display for individualviewing. Nevertheless, the monitor 28 may display a selected screen 210that may include any appropriate portion.

For example, the screen 210 may include a top section 212 thatillustrates an anterior/posterior plane view or a representation of thefirst screw 206. The representation of the first screw 206, is asubstantially virtual first screw 206′ on the screen 210. The locationof the first screw 206 can be illustrated as the virtual first or firsticon screw 206′ due to the detection by the detector 22 of thelocalization element 104. Although other appropriate mechanisms may beused to localize the first screw 206. The screen 210 may also include abottom portion or second portion 216 that illustrates a substantiallylateral plane view of the first screw 206 as a cross-section or profileof the first virtual screw 206′. It will be understood that anyappropriate views may be represented on the screen 210 and onlyincluding the anterior posterior plane view in section 212 and thelateral plane view in section 216 is simply exemplary and not intendedto limit the present disclosure. Nevertheless, the virtual screw 206′may illustrate the rotational position, the trajectory, the location,and any other attributes collected due to the saving of the firstposition of the first screw 206.

In addition, the monitor 28 may be a touch sensitive monitor, such thattouch button 210 may be included on the monitor 28. The touch buttonsmay allow for the selection of which localization element is connectedto the screw and may be used for later navigation purposes. It will beunderstood, however, that the touch buttons 218 are merely exemplary andnot required. For example, the touch buttons 218 may also be selectableby a pointer device, such as a generally known mouse, or commands andselections may be substantially manually entered with a keyboard or thelike.

With reference to FIG. 8A and continuing reference to FIG. 6, a secondscrew 220 may be positioned in a second vertebrae 222. Positioning thesecond screw 220 is exemplary of placing a second member in block 156.The second screw 220 is also generally positioned through the dermis 202through an incision 224 formed therein. It will be understood that thesecond screw 220 is generally positioned through similar soft tissue asthe first screw 206. Therefore, the screw 220 can be positioned into thesecond vertebrae 222 through any generally known method.

The position of the second screw 220 may then be determined, such asdetermining the position of a second member in block 158 of the method146, using a second of the localization element 106. The secondlocalization element may include the extender 126, which is able tooperably engage the second screw 220. As discussed above, the extender126 may engage the second screw 220 in any appropriate manner, which mayinclude a substantially quick release manner using the levers 134. Thesecond localization element 106 generally includes the tracking element112, which includes the navigation areas 128, 130 and 132, such that thedetector 22 may detect the position of the tracking element 112. Thedimensions of the extender 126 relative to the second screw 220 and atracking element 112 are generally known and can be selected using thecomputer 24. Also, as discussed above, the position of the second screw220 may be determined using any appropriate mechanism.

Therefore, the detector 22 may detect the position of the trackingelement 112 and transmit the information to the computer 24, such thatthe location of the second screw 220 may be determined bothindependently and/or relative to the first screw 206. The position ofthe second screw 220 may be saved, such as saving the position of thesecond member in block 160 of the method 146. As with the position ofthe first screw 206, the position of the second screw may be illustratedon the screen 210. Alternatively, the navigated needle or probe 236(FIG. 9B) may be used to sense the location of the second screw. Aftersensing the location of the second screw 220, its location may be knownrelative to the first screw 206. When the localization element 108 isnot attached to the second screw 220, the dynamic reference frame 38 maybe referenced to determine the position of the second screw 220 if thereis any movement of the vertebrae. It will be understood any number ofimplant portions may be sensed. In addition, a plurality of constructsmay be sensed and interconnected. Therefore, providing only oneconstruct or one connector is merely exemplary and not limiting.

With reference to FIG. 8B, after the detector 22 has detected theposition of the second screw 220, a second virtual screw 220′ isillustrated on the monitor 28. The screen 210 may change to illustratethe second virtual screw 220′. Substantially similar views of the secondvirtual screw 220′ may be illustrated similar to those of the firstvirtual screw 206′. For example, an AP plane view of the second virtualscrew 220′ may be illustrated relative to the first virtual screw 206′,such that the relative locations and measurements may be obtainedrelative to the first virtual screw 206′. Similarly, a lateral planeview may illustrate a substantially cross section or profile view of thesecond virtual screw 220′ similar to the virtual first screw 206′.Nevertheless, the monitor 28 is able to illustrate on the screen 210 therelative position of the first screw 206 as the first virtual screw 206′and the second screw 220 as the second virtual screw 220′.

Once the location of the first screw 206 and the second screw 220 havebeen saved on the navigation computer 24 the relative distances,orientations, and the like may be illustrated on the screen 210.Therefore, a user is able to determine the position, location,displacement, and other attributes of the first screw 206 relative tothe second screw 220, although the first screw 206 is not viewable andneither is the second screw 220 through the dermis 202. The virtualdisplay of the first virtual screw 206′ is displayed relative to thedisplay of the second virtual screw 220′ so that this information may beknown.

With reference to FIG. 9A, the information displayed on the screen 210illustrates a substantially virtual view of the anatomical occurrences.Therefore, the anatomical portion may not change, but the screen 210 andthe computer 24 operably connected thereto may be used to plan furtherportions of the procedure.

The first virtual screw 206′ and the second virtual screw 220′ may beshown alone on the screen 210 or may be shown in conjunction with animage of the spine 200. The image of the spine may be an image acquiredpre- or intra-operatively of the patient 40. For example, if thefluoroscopic device 52 is included in the procedure, a real-time imageof the spine 200 may be taken and illustrated relative to the firstvirtual screw 206′ and the second virtual screw 220′ on the screen 210.The first screw 206 and second screw 220 may also be generally radialopaque. Therefore, the image taken of the spine 200, including the firstscrew 206 and the second screw 220, may be used to verify therepresentation of the first virtual screw 206′ to the second virtualscrew 220′. In addition, the image of the spine may be superimposed overthe first virtual screw 206′ to the second virtual screw 220′ to give avisual cue of the anatomical portions specifically near the screws 206and 220. Although the inclusion of the image of the spine is notnecessary, it may be selected to include the image of the spine.

The image of the spine may also be achieved by using a generally knownatlas that is morphed to the patient 40 using pre-acquired orintra-operatively acquired images. The morphed atlas image may bemorphed relative to the specific anatomy of the patient 40. In addition,the position of the screws in the anatomy may be known and the morphedatlas image of the spine be morphed or augmented, such that the knownlocations of the first screw 206 and second screw 220 substantially meetthe size indications of the morphed atlas image. Therefore, the spineimage may either be an image of the patient 40 or a morphed atlas imagethat may be stored in the navigation computer or accessed by thenavigation computer 24.

Nevertheless, and as may be typically performed, a virtual orrepresentative spine 200′ may be displayed as an icon or representationof the spine 200. The virtual spine 200′ may be a generally known atlasmodel or computer generated representation of the vertebrae relative tothe screws 206 and 220. Therefore, the display may include the icons ofthe screws 206′ and 220′ also, or in addition, to an icon or graphicalrepresentation of the spine 200. The virtual spine 200′ is notnecessarily directly representative of the spine 200 and may simply befor user comfort while the positions of the screws 206 and 220 are knownand represented as the first virtual screw 206′ and the second virtualscrew 220′.

If a virtual image, such as from an atlas model or a 3D model, is usedto form the virtual spine 200′ on the screen 210, the atlas or 3D modelmay be morphed relative to any known measurement. For example, the 3Dmodel or atlas model may be morphed relative to the size of the screwsimplanted into the spine 200. Therefore, the atlas or 3D model may bemorphed or scaled to the size of the implanted screw due to the inputtedinformation about the screw into the navigation computer 24. Informationregarding the size of the screw relative to a size of the vertebrae orthe pedicle into which the screw is placed may be used for the scaling.Therefore, a generally known atlas or 3D model may be morphed knowingthe size of the screws implanted or any other known measurement, such asalso a pre- or intra-operatively acquired image, if one is acquired.

Regardless of whether the screen 210 includes the virtual spine 200′ oran image of the spine 200, the determination of various aspects of theprocedure may occur. For example, an alignment in the AP plane may beselected or suggested, such as selecting an alignment in the first planein block 162. An alignment display line 226 may be displayed in the APsection 212 of the screen 210. The anterior posterior alignment line 226may either be selected by a user or suggested by the navigation computer24 depending upon selected inputs. The anterior posterior alignment line226 may be used for any purpose, such as ensuring a substantiallystraight line between the first screw 206 and the second screw 220, suchas represented by the first virtual screw 206′ and the second virtualscrew 220′. Nevertheless, it will be understood that the alignment line226 may be used to choose any appropriate or selected alignment of theanatomy relative to the virtual screws 206′ and 220′ or to any portionoutside of the virtual screws 206′ and 220′. That is, the alignment line226 may be used to align a position generally between the first virtualscrew 206′, therefore, the first screw 206 and the second screw 220′,and therefore, the second screw 220, or to any point outside of the twoscrews 206 and 220.

In addition, an alignment in a second plane, such as the lateral plane,illustrated in the second section 216 may be selected or chosen, such asselecting alignment in a second plane in block 164. Any appropriatealignment, such as a selected radii may be illustrated or chosen in thesecond section 216. For example, three possible radii 228, 230, and 232may be illustrated between the first virtual screw 206′ and the secondvirtual screw 220′. The radii may be suggested by the navigationcomputer 24 or selected by the user. Nevertheless, a plurality of theradii lines may be illustrated in the second section 216 of the screw210 for selection and use by the user. The display of the variousalignments or radii in the second section 216 allows the user todetermine or select the radii most appropriate for the procedure.

With continuing reference to FIG. 9A, once the alignment has beenselected, such as the alignment of alignment line 226 and the alignmentof alignment line 230, as only an example, a navigated instrument may beused to achieve a selected location and trajectory of a third screw 240(FIG. 10A) such as determining a location and trajectory of a thirdmember in block 166. Any appropriate instrument may be used to selectand navigate a trajectory of the third screw 240. For example, anavigated needle may be used to achieve the initial location andtrajectory of the third screw in a third vertebrae 234 (FIG. 10A).

With continuing reference to FIG. 9A and additional referenced to FIG.9B a navigated needle 236 may be used to touch one or a plurality ofpoints on the third vertebrae 234. The navigated needle 236 may use anyappropriate navigational location system and may include a locating ortracking element, such as those described above, such that the detector22 may detect the location of the needle 236 and it may be displayed onthe monitor 28. A virtual navigated needle 236′ may be shown as acrosshair in the AP section 212 of the screen 210 and may be shown as apointer in the lateral plane view section 216. In addition, a optimallocation 238 may be shown on the screen 210 as a circle or otherindication for locating a trajectory of the third screw. Therefore, thenavigated needle 236 may be used to illustrate a virtual navigatedneedle location 236′ on the screen 210 such that the navigated needle236 may be moved until it substantially intersects the optimal location238 illustrated on the screen 210. The navigated needle 236 may then beused to form a pilot hole or point in the third vertebrae 234 forinitial locating and driving of the third screw.

The navigating computer 24 may form the optimal location 238 displayedon the monitor 28 as a location on the screen 210 such that thenavigated needle 236 may be moved to substantially reach in theanatomical spine 200 the optimal or suggested location illustrated onthe screen. The virtual navigated needle 236′ allows the user to movethe navigated needle 236 and see a location of the navigated needle 236on the screen 210 as the virtual navigated needle 236′ such that thenavigated needle may be moved relative to the spine 200 without the useractually viewing the spine 200 or a tip of the needle 236. Thenavigation computer 24 may calculate the optimal location 238 forplacement of the third screw due to the selection of the alignmentplanes 226 and 230.

Once the navigational needle 236 has reached the optimal location 238determined by computer 24 or selected by the user the third screw 240may be inserted into the third vertebrae 234. The third screw 240 may beinserted into the position pierced with the navigation needle 236. Thepiercing by the navigation needle 236 may provide an initial trajectoryfor placing the third screw 240 into the third vertebrae 234.Nevertheless, to insure the achievement of the selected radii, the thirdscrew 240 may need to be inserted to a selected depth. Therefore, thethird screw 240 may be navigated using the navigation computer 24 todisplay the screen 210 that includes the third screw 240 as a thirdvirtual screw 240′.

With reference to FIG. 10A, the positioning of the third screw 240 maybe guided and navigated using the navigation computer 24 and viewing thevirtual third screw 240′ on the screen 210. Alternatively, navigationneedle 236 may be used to engage a top of the third screw 240 thusallowing the determination of the position on the third screw 240 fordisplaying the third virtual screw 240′. Alternatively, the thirdlocation element 108, including the tracking element 114 positioned onthe extender 136, may engage the third screw 240. Using thesubstantially quick release mechanism the localization element 108 maybe quickly engaged and disengaged from the third screw 240. Therefore,the third screw 240 may be positioned in a first location and thelocalization element 108 be positioned relative to the third screw 240and a location of the third screw 240 be determined.

The first position of the third screw 240 may be illustrated as 240′ inphantom as illustrated in FIG. 10B. The phantom location of the virtualscrew 240′ may indicate that the third screw 240 must be further driveninto the third vertebrae 234 to achieve the selected location.Therefore, the location element 108 may be removed from the third screw240 such that the third screw may be driven further into the thirdvertebrae 234. After the adjustment of the third screw 240 thelocalization element 108 may be reengaged to the third screw 240 and thelocation again determined of the third screw 240. This process may berepeated any appropriate number of times to guide the positioning of thethird screw such as guiding the positioning of the third member in block170. It will also be understood that any appropriate mechanism may beused to navigate the movement of the third screw 240. As discussedabove, various mechanisms may either be included in the third screw 240or attached to the third screw 240 rather than using the imaged basedsystem. Nevertheless, the positioning of the third screw 240 can besubstantially navigated using the navigation computer 24 such that theplacement of the third screw 240 can be substantially precisely placed.

It will be understood that very precise placement of the third screw240, or any of the screws 206 and 220, may not be necessary when anon-rigid fourth member or connector is used. For example, the thirdscrew 240 may be navigated to a selected position, such as one to insurea selected purchase in the third vertebrae 234, and a deformableconnector may then be used to interconnect each of the screws 206, 238,and 240. The flexible or deformable connector may be an injectablecatheter, a cord, or other appropriate deformable connector. Therefore,it will be understood that the navigation of the positioning of thethird screw 240, or any of the screws 206, 220 or any other number ofscrews, may be navigated such that the screws achieve a selectedcharacteristic, such as a purchase in the selected vertebras, and adeformable or selected connector may be used to interconnect the variousscrews.

When a rigid connector is being used, however, the screen 210 and thenavigation computer 24 may be used to determine a characteristic of aconnector. For example, with reference to FIG. 10B, if a rigid rod isbeing used to interconnect the screws 206, 220, and 240, the display mayindicate a rod length 242 and a rod radius 244. Therefore, thenavigation computer 24 may assist in the selection of an appropriate rodand assist in placing the screws 206, 220, and 240 to achieve thisselected rod characteristics. The determination of the appropriate rodand characteristics may be similar to that performed in block 172.

After the appropriate characteristic or selected characteristic isdetermined, the plan, including the selected rod to interconnect thescrews 206, 220, and 240, may be determined such as determining the planand selection of fourth member block 174. After the plan is determined,the user may either reject the plan such as in block 176 or accept theplan in block 178. If the plan illustrated on the screen 210 is rejectedthe third screw 240 may be navigated to a different position. Therefore,the steps described above may be repeated to position the third screw240 in a different selected location and which may be illustrated on themonitor as the virtual third screw 240′. Again, the localization element108 may be used to determine the location of the third screw 240 andillustrate the location of the third screw 240 on a screen 210.

If the plan for selection of the connector is accepted, as in block 178,the rod may be operably interconnected with a navigable instrument. Withreference to FIG. 5, the connector 88 may include the exemplary rod 92which includes the selected characteristics, such as a rod length of 75mm and a rod radius of 196 mm. Nevertheless, it will be understood thatdifferent connectors may have different radia and lengths.

Nevertheless, the rod 92 is generally interconnected with the instrument36 which includes the tracking element 230. The rod 92 is generallyfixed at the proximal end 92 b to a portion of the instrument 36 that isable to substantially selectively hold the rod 92 during theimplantation. The selection of the rod may then be accepted or inputtedinto the computer 24 such that a computer 24 knows the length of the rod92 extending from the instrument 36. The rod 92 and its distal endpoint92 a may then be calibrated and verified, such as in block 186. This mayinclude the stored data regarding the rod 92 or through various tests tolocate the distal end 92 a of the rod 92 in the instrument 36.Therefore, because the rod 92 and the instrument 36 have beencalibrated, the navigation computer 24 is able to determine the locationof the distal end 92 a of the rod 92 by the detection by the detector 22of the tracking elements 230 affixed to the instrument 36. Nevertheless,it will be understood that any appropriate tracking element may extendor be incorporated with the instrument, such as various EM coils. Inaddition, the rod 92 may include various tracking elements such as coilsthat may be detected in an EM navigation system or other appropriatenavigation systems. Nevertheless, regardless of the apparatus or methodchosen, the location of the rod 92 is able to be determined by thenavigation computer 24 and navigated and illustrated on the screen 210.

With reference to FIGS. 11A and 11B the position of the dermis 202 maybe determined relative to the spine 200. Although, as discussed above,determining the location of the soft tissue 202 relative to the spine200 is not necessary. It may assist in determining an appropriate pathof the rod 92 through the screws 206, 220, and 240. Therefore, aselected instrument such as the dermal topography instrument 246 may beused to trace or determine various points of the dermis 202. The dermistopography instrument 246 may include a tracking element 248 thatincludes navigation points 250, 252 and 254. As discussed above, thetracking element 248 may be detected using the detector 22 to determinea location of a distal tip 256 of the dermal topography instrument 246.The dermal topography element 246 may be traced over or touched to aplurality of points on the dermas 202 such that a virtual dermal layer202′ may be illustrated on the screen 210. Therefore, the dermal layeror location of the soft tissue may be illustrated on the screen 210 andlocation determined such as determine a location of selected soft tissuein block 180.

After the dermal tissue has been located and illustrated on the screen210 an entry point 258 may be selected or determined with the navigationcomputer 24 and illustrated as a virtual entry point 258′ on the screen210. Therefore, the location of a entry 258 may be selected dependingupon the topography of the dermis and other selected soft tissues.Nevertheless, it will be understood that the determination of an entrypoint such as in block 182, may be determined without providing anoutline of the dermas 202. In addition, the entry point may be selectedby a user regardless of the topography of the dermas and may be selectedbased upon other considerations. Nevertheless, the navigation computer24 is able to illustrate the dermal layer 202 relative to the screws206, 220, and 240 on the screen 210. In addition, as discussed above, avirtual spine may overlay the virtual screws 206′, 220′ and 240′ on thescreen 210. Therefore, a substantially complete anatomical view may bedisplayed on the screen 210 including both an outline of the dermas 202as a virtual dermal outline 202′ and a spine.

It will also be understood that if the fluoroscopic device 50 isincluded that an image may be taken at any appropriate time to confirmthe location of the screws 206, 220, and 240 in the spine 200 as locatedon the screen 210. Therefore, an image may be taken intra-operatively,or at any other appropriate time, to confirm the location of the screwsin the spine 200. This image may also be viewed on the screen 210 ratherthan a preoperative or a atlas image.

With reference to FIGS. 12A and 12B after the rod 92 has been calibratedrelative to the instrument 36, the implantation of the rod 92 mayproceed. With particular reference to FIG. 12B the first section 212 ofthe screen 210 may change to a Dynamic Trajectory view of the distal end92 a of the rod 92 being illustrated as a crosshair 260 relative to acircle or other appropriate shape as a desired path 262. The progress ofthe rod 92 along the planned route may also be illustrated as a bar orother graphic 264. It will also be understood that the progress may beillustrated using a numerical indication, such as a percent.

The distal end 92 a of the rod 92 is localized, prior to the beginningof the procedure, such as in block 188. After the distal end 92 a of therod 92 has been localized, the navigation computer 24 may be used tonavigate and illustrate the movement of the rod on the screen 210.Therefore, the movement of the rod may be tracked such as the fourthmember may be tracked and guided, such as in block 190. the position ofthe distal end 92 a of the rod 92 is illustrated as the crosshair 260such that the user is able to determine whether the distal end 92 a ofthe rod 92 is positioned relative to the desired path as illustrated asa desired path 262.

In addition to the numerical graphical progress illustrated in the firstpart 212 of the screen 210, a virtual location of the rod 92 may beillustrated as the virtual rod 92′ on the lateral plane view of thescreen 210. In addition, the distal tip 92 a may be illustrated as avirtual distal tip 92 a′. Therefore, a virtual image of the progress ofthe rod 92 may be illustrated on the monitor 28 as determined by thenavigation computer 24. The position of the rod 92 is known and may bedetermined due to the fact that the rod 92 is generally fixed to theinstrument 36 which includes the tracking elements 230. The detector 22may detect the tracking element 230 to determine the position of theinstrument 36 and the navigation computer 24 is able to then determinethe location of the rod 92 and the distal tip 92 a. The position andmovement to the distal tip 92 a can be known and illustrated as thevirtual distal tip 92 a or the crosshair 260. In this way, the positionof the distal tip 92 a of the rod 92 can be illustrated for bothdetermining and insuring that the distal tip 92 a is moving along theselected path 262 and the virtual progress of the rod 92 through thespine 200. Therefore, the progress of the rod 92 may be indicated as theprogress of the fourth member in block 192.

It will be understood, however, that the rod 92 may also include othertracking elements, such as coils that may be detected with an EMdetector, rather than including the tracking element 230 on theinstrument 36. In addition, the connector 92 or a similar connector, maynot necessarily be a substantially rigid member. Rather the connectormay be a substantially navigable or steerable catheter which may besteered relative to the screws 206, 220, and 240. Therefore, the dynamictrajectory section of the screen 210 may illustrate or show the distalend of the steerable catheter relative to the selected path 262.Nevertheless, the selected path, 262 may be generally discontinuous suchthat the steerable catheter may be steered to achieve the selected path262. Therefore, the steerable catheter may be inserted relative to thescrews 206, 220, and 240 in a selected manner using the navigationcomputer 24 and the monitor 28 such that a substantially complexinterconnection can be formed without a generally open procedure tocompletely view the spine 200.

With reference to FIGS. 13A and 13B, the connector 92 may generallyinterconnect each of the three screws 206, 220, and 240. The navigationof the connector 92 may also be useful in determining the achievement ofthe distal end 92 a of the connector 92 at the pre-selected end pointrelative to the one of the screws. As exemplary illustrated here thesecond screw 220 substantially defines an end point of the movement ofthe connector 92. Therefore, the navigation computer 24 is able todetermine the achievement of the end point by the fourth member such asin block 194. The screen 210 may illustrate this achievement of the endpoint by illustrating the virtual rod 92′ positioned at a selectedposition relative to the virtual screws on the screen 210. In addition,various indications such as word indications 266 including FINISHED maybe illustrated on the screen 210 to notify the user that thepredetermined plan has been achieved. In addition, the virtual rod 92′may change colors, an audible signal maybe created, or any otherappropriate signal may be used to signal the user that the predeterminedplan has been achieved. Generally, the procedure is then ended such asin block 196. Nevertheless, various other actions may be taken such asremoving the instrument 36 from the rod 92, suturing the incisionsformed for the insertion of the screws, and removing the localizationelements 104, 106, and 108, or any other appropriate measures that areselected to be taken to complete the implant procedure. In addition,after the various localizers and other elements are removed, the screwsare generally tightened onto the connector 92. This may occur in anyappropriate manner, such as locking the multi-access screws in aselected position, tightening the screw relative to the bone to hold theconnector 92 relative to the bone, or any other appropriate manner.Generally, the navigation allows the connector to be positioned relativeto the screws and afterwards, the screws are locked relative to theconnector.

In addition, the optional imaging system 50 may be used to acquire animage of the patient 40 for display on the monitor 28. The optionalimage acquired of the patient 40 may also be used to confirm properplacement of the construct 88 in the patient 40. Also, as illustrated inFIG. 13B, the acquired image of the patient 40 may be superimposed overthe icons representing the screws 206′, 220′ and 240′ and the rod 92′,to confirm proper or selected placement of the construct. Again, asdiscussed above, an image of the patient 40 is not required to performthe procedure thus the optional imaging system 50 is not necessary toacquire an imaging of the patient 40.

Therefore, the construct 88 may be implanted in the patient 40 through asubstantially minimally invasive procedure. The incisions though thedermis 202 may be kept small thus reducing trauma and minimizing directvisualization of the anatomy. Nevertheless, the imageless navigationsystem 20 may be used to track, guide and assist in the implantationpercutaneously.

According to the above, a multi-level or geometrically constrainedconstruct, such as the spinal implant 80, may be implanted relative to aspine through a substantially less invasive or percutaneous procedure.The implantation of the construct 80 relative to the spine 200 mayinclude a plurality of elements, such as the three or more screws 206,220, and 240 or any appropriate number of screws and the connector 88 tointerconnect each of the screws. Although the above discussion includedthree screws only one or more than three may be used. In addition, thenavigation computer 24 may be used when the connector 88 is of aselected and/or constrained geometry.

The navigation computer 24 may be used to navigate the connectorrelative to the plurality of screws such that a selected position, whichmay be a substantially complex position, of the connector can beachieved. In addition, the selected position of a connector may beachieved without substantially mechanical means or apparatus required tomove the connector relative to the screws. Rather, the navigationcomputer 24 is able to navigate the connector, such as the rod 92,relative to the other elements of the construct.

Although the above discussion has exemplary illustrated the method toimplant a construct relative to a spine it will be understood that anyother appropriate construct may be implanted. For example, thenavigation system may be used to navigate an acetabular implantsubstantially percutaneously. The positions of the acetabular implantmay be determined using localization or tracking elements and theplacements of other elements relative to selected portions of theanatomy or other portions implanted may be navigated with the navigationcomputer. Therefore, the navigation computer 24 may be used to navigatethe implantation of any appropriate implant through a generallypercutaneous and/or minimally invasive procedure.

It will be understood that the above is merely exemplary of applicationsof the present disclosure and appended claims. For example, although theabove description is related to implanting a connector relative to aplurality of screws, it will be understood that the informationcollected into the navigation computer 24 may also be used to customizea connector. Therefore, a connector may be bent either manually orautomatically to interconnect the plurality of screws. In addition, akit may include a plurality of connectors, such as the kit illustratedin FIG. 3, to allow for the selection of a connector that substantiallyinterconnects the screws 82 in a selected manner. Therefore, the method146 may be used to implant a connector relative to a plurality of screwsin any appropriate manner. Also, the navigation computer 24 and themethod 146 generally allows for the connection of a plurality of points,such as three or more. Therefore, a complex geometry, such as aconstrained geometry, can be easily achieved by use of the presentlydescribed invention. Therefore, a mechanical alignment device is notnecessary, though it may be used.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A system for use in navigating an implantation of a human spinalimplant, comprising: a first pedicle screw member and a second elongatedrod member of the construct adapted to selectively interact with eachother after implantation and said first pedicle screw member operable tobe fixed into a boney structure; a third pedicle screw memberpositionable relative to said first pedicle screw member and said secondelongated rod member in an anatomical portion; a first localizationelement selectively and removably fixed to said first pedicle screwmember having a depressible member to operate an internal mechanism toengage and disengage from said first pedicle screw member; a secondlocalization element selectively and removably fixed to said secondelongated rod member; a detector operable to detect said firstlocalization element and said second localization element when saidfirst localization element and said second localization element isselectively fixed to at least one of said first pedicle screw member orsaid second elongated rod member; and a processor configured to: assistin navigation of said second elongated rod member relative to said firstpedicle screw member; receive position information for all of said firstpedicle screw member, said second elongated rod member, and said thirdpedicle screw member from said detector; determine a relative positionbetween all of said first pedicle screw member, said second elongatedrod member, and said third pedicle screw member; assist in navigation ofsaid third pedicle screw member relative to at least one of said firstpedicle screw member or said second elongated rod member includinggenerating icons for display on a display device without patient imagedata displayed on the display device; and simultaneously track saidfirst localization element while selectively fixed to said first pediclescrew member and said second localization element while selectivelyfixed to said second elongated rod member.
 2. The system of claim 1,wherein said first pedicle screw member includes a fastener operable tobe fixed to a selected anatomical portion having a first fixable portionfor being fixed to the selected anatomical portion and a secondengageable portion to be connected to said second elongated rod member;wherein said second elongated rod member includes a connector tooperably interconnect said first pedicle screw member and said thirdpedicle screw member.
 3. The system of claim 2, wherein said thirdpedicle screw member is selected from a group including a fastener, aconnector, an anatomical portion, and combinations thereof.
 4. Thesystem of claim 2, wherein said fastener includes a screw with a shankand an adjustable head operable to be positioned into a vertebra;wherein said localization element is operable to be connected to saidadjustable head; wherein said processor is operable to determine aposition of the adjustable head.
 5. The system of claim 1, wherein saidfirst pedicle screw member and said second elongated rod member are eachfasteners having a fastener portion and an engageable portion; whereinsaid third pedicle screw member is a connector operable to interconnectsaid first pedicle screw member and said second elongated rod member ina selected orientation.
 6. The system of claim 1, wherein saidlocalization element is selected from a group comprising anelectromagnetic tracking device, an optical tracking device, aconductive tracking device, a fiberoptic tracking device, an acoustictracking device, and combinations thereof.
 7. The system of claim 1,wherein said detector is selected from the group comprising anelectromagnetic detector, an optical detector, a conductive detector, afiberoptic detector, an acoustic detector, and combinations thereof. 8.The system of claim 1, wherein said first localization element includesan extender operable to be removably connected to said first pediclescrew member; and a first tracking element operable to be detected bysaid detector to detect a position of said first tracking element in adetector space; and said second localization element includes anextender operable to be removably connected to said second elongated rodmember and a second tracking element operable to be detected by saiddetector to detect a position of said second tracking element indetector space.
 9. The system of claim 8, wherein said processor isoperable to determine a position of at least one of said first pediclescrew member or said second elongated rod member after detection of saidtracking element by said detector.
 10. The system of claim 8, whereinsaid localization element includes a plurality of localization elementssuch that each of said first pedicle screw member and said secondelongated rod member includes a localization element extendingtherefrom.
 11. The system of claim 8, wherein the first tracking elementhas a first shape and the second tracking element has a second shapedifferent from said first shape such that said detector or saidprocessor can uniquely identify each of said first pedicle screw memberand said second elongated rod member.
 12. The system of claim 1, furthercomprising: a fourth member; wherein said first pedicle screw member,said second elongated rod member, and said third pedicle screw memberare operable to be fixed relative to the anatomical portion; whereinsaid processor is operable to determine a real time position of saidfourth member relative to said first pedicle screw member, said secondelongated rod member, and said third pedicle screw member tosubstantially position said fourth member in a selected positionrelative to said first pedicle screw member, said second elongated rodmember, and said third pedicle screw member.
 13. The system of claim 1,wherein said second elongated rod member is substantially navigated atleast one of percutaneously or minimally invasively.
 14. The system ofclaim 1 further comprising: a navigable needle positionable relative toat least one of said first pedicle screw member or said second elongatedrod member such that said navigation system is operable to determine aposition for the third member relative to said of at least one of saidfirst pedicle screw member or said second elongated rod member.
 15. Thesystem of claim 1, wherein said processor assists in providing analignment of said of at least first pedicle screw member or said secondelongated rod member in at least two planes.
 16. The system of claim 1,wherein said second elongated rod member is selected from a groupcomprising a substantially rigid rod, a steerable connector, adeformable connector, a flexible connector, and combinations thereof.17. The system of claim 1, wherein said display displays arepresentation of at least one of said first pedicle screw member orsaid second elongated rod member with an icon.
 18. The system of claim17, wherein said display displays an atlas map superimposed over saidicon.
 19. The system of claim 1, wherein said processor is operable totrack said first localization element fixed to said first pedicle screwmember and said second localization element fixed to said secondelongated rod member with six degrees of freedom.
 20. The system ofclaim 1, wherein said first localization element engages with said firstmember and locks said first pedicle screw member in a selected positionand a selected orientation.
 21. A system for use in determining aposition of a first implantable member and planning and navigatingrelative to the first member for positioning a second member to interactwith said first member, the system comprising: the first memberincluding a bone engaging portion for fixation to a boney structure; atracking element interconnected with the first member operable to beused to determine a position of the first member; a first detectoroperable to detect said tracking element; a processor configured todetermine a position of the first member depending upon the detection ofsaid first detector; a navigable instrument operable to move the secondmember relative to the first member; a second detector operable todetect said navigable instrument; and a display to display a first iconrepresenting a first location of the first member and a second iconrepresenting a second location of the second member; wherein thetracking element remains connected to the first member during themovement of the navigable instrument; wherein said processor isconfigured to determine a position of the second member relative to thefirst member in at least two planes; wherein said processor isconfigured to navigate said navigable instrument relative to saidtracking element for positioning of the second member relative to thefirst member in a substantially patient imageless display; and whereinsaid processor is configured to track the tracking element fixed to saidfirst member while tracking said navigable instrument; wherein thesubstantially patient imageless display includes said first icon andsaid second icon representing the first member and the second member inthe at least two planes with no displayed images of the patient.
 22. Thesystem of claim 21, wherein said first detector and said second detectorare a single detector.
 23. The system of claim 22, wherein said detectoris selected from the group comprising an electromagnetic detector, anoptical detector, a conductive detector, a fiber optic detector, anacoustic detector, and combinations thereof.
 24. The system of claim 21,wherein said navigable instrument is operable to engage the secondmember to move the second member relative to the first member.
 25. Thesystem of claim 21, wherein said processor is operable to navigate saidnavigable instrument relative to said tracking elements such that saidsecond member is moved to a selected position relative to said firstmember substantially at least one of percutaneously or minimallyinvasively.
 26. The system of claim 21, further comprising: an imagingdevice to acquire a patient image after the first member and the secondmember are navigated in the substantially patient imageless manner of aselected portion relative to at least one of the first member or thesecond member and to display the acquired image data relative to saidfirst icon and said second icon representing the first member and thesecond member to confirm the displayed position of at least one of thefirst member or the second member.
 27. The system of claim 21, whereinsaid processor provides an alignment along at least two planes relativeto the first member or the second member.
 28. The system of claim 27,wherein said planes are substantially orthogonal including a view alonga longitudinal axis of the first member and a view transverse to thelongitudinal axis of the first member.
 29. The system of claim 21,wherein said processor determines the position of the first member andthe second member without images of the patient.
 30. The system of claim29, further comprising: a display to display a first icon to represent aposition of the first member and a second icon to represent a positionof the second member relative to said first member.
 31. The system ofclaim 30, wherein said processor superimposes an atlas model over thefirst icon and the second icon.
 32. The system of claim 21, wherein saidprocessor is operable to track the tracking element fixed to said firstmember with six degrees of freedom.
 33. The system of claim 21, whereinthe tracking element engages with said first member and locks said firstmember in a selected position and a selected orientation.
 34. The systemof claim 33, wherein said tracking element includes a depressible membercoupled to a mechanism that selectively engages and disengages with saidfirst member.
 35. A method of implanting a construct having at least afirst member, a second member, or a third member, the method comprising:positioning the first member into a first boney structure; tracking aposition of the first member in a selected space with a first trackingelement connected to the first member; positioning the second member ina second boney structure relative to the first member; tracking aposition of the second member in the selected space with a secondtracking element connected to the second member while positioning thesecond member relative to the first member; navigating the third memberrelative to the first member and the second member, while tracking thefirst tracking element connected with the first member and tracking thesecond tracking element connected to the second member, including:determining with a processor a real time optimal position of the thirdmember in the selected space; and determining a real time position ofthe third member relative to at least one of the first member or thesecond member; displaying an icon on a display to illustrate thedetermined real time optimal position of the third member; anddisplaying an icon to represent the position of at least two of thefirst member, the second member, or the third member without displayingimages acquired of the patient on the display.
 36. The method of claim35, further comprising saving at least one of the determined position ofthe first member or the determined position of the second member. 37.The method of claim 35, wherein said tracking element is selected from agroup comprising an electromagnetic tracking device, an optical trackingdevice, a conductive tracking device, a fiber optic tracking device, anacoustic tracking device, and combinations thereof.
 38. The method ofclaim 35, further comprising: displaying the determined real timeposition of said third member on a display; wherein said display assistsa user in moving the third member relative to the optimal position. 39.The method of claim 35, further comprising: selecting a characteristicof the third member for implantation relative to the first member andthe second member; and positioning a fourth member relative to saidfirst member and said second member to be interconnected by said thirdmember in the selected orientation.
 40. The method of claim 35, whereinpositioning the first member, positioning the second member, andnavigating the third member includes at least one of percutaneous orminimally invasively placements of at least one of a pedicle screw or aconnector.
 41. The method of claim 40, wherein navigating the thirdmember includes at least one of percutaneously or minimally invasivelymoving the third member relative to the first member and the secondmember to interconnect the first member and the second member.
 42. Themethod of claim 35, wherein at least one of determining a position ofthe first member or determining a position of the second member includesassociating a trackable probe to at least one of the first member or thesecond member.
 43. The method of claim 35, wherein determining a realtime position of the third member includes knowing substantially onlythe position of the third member relative to at least one of the firstmember or the second member.
 44. The method of claim 35, whereintracking comprises tracking the first tracking element connected to thefirst member and the second tracking element connected to the secondmember with six degrees of freedom.
 45. The system of claim 35, whereinsaid first tracking element engages with said first member and lockssaid first member in a selected position and a selected orientation. 46.The system of claim 45, wherein said first tracking element includes adepressible member coupled to a mechanism that selectively engages anddisengages with said first member.
 47. The method of claim 35, furthercomprising: connecting a third tracking element to the third member toallow said navigating the third member; wherein the first member is afirst pedicle screw, the second member is a second pedicle screw, andthe third member is an elongated rod moveable to interconnect the firstpedicle screw and the second pedicle screw.
 48. The method of claim 47,further comprising determining a selected alignment relative to saiddetermined position of the first member and said determined position ofthe second member.
 49. The method of claim 48, further comprising:selecting a characteristic of at least one of the first member, thesecond member or the third member from a group including a length, aradius, a diameter, an offset, a flexibility, an alignment, orcombinations thereof.
 50. The method of claim 49, further comprising:verifying a final position of the third member relative to at least oneof the first member or the second member.
 51. The method of claim 50,wherein verifying the position of the third member includes obtaining animage of an area including at least one of the first member or thesecond member and said third member.
 52. The method of claim 47, whereindetermining a real time optimal position includes processing with aprocessor regarding at least two planes a determination of a real timeoptimal position along at least two planes for the third member.
 53. Themethod of claim 52, wherein said two planes are substantially orthogonalto each other including displaying on a display device a first iconrepresenting a top view of the elongated rod and displaying a secondicon representing a side view of the elongated rod.
 54. The method ofclaim 47, further comprising: determining a contour of a soft tissuewithout patient images by tracking an instrument that is moved relativeto the soft tissue; wherein determining a real time optimal positionincludes determining an insertion point through the soft tissue for theelongated rod.
 55. The method of claim 54, wherein determining a contourof the soft tissue includes moving a navigable probe that is tracked andcontacting the soft tissue to determine a contour of the soft tissuerelative to the boney structure with a processor for determining theinsertion point.
 56. The method of claim 47, wherein connecting atracking element includes depressing a member to actuate an internalmechanism to fixedly connect the tracking element to the first pediclescrew; while the tracking element is fixedly connected to the firstpedicle screw also tracking the second pedicle screw with a secondtracking element fixedly connected to the second pedicle screw.
 57. Amethod of implanting a construct of at least a first member, a secondmember, or a third member substantially at least one of percutaneouslyor minimally invasively, comprising: selecting a final orientation of atleast one of the first member, the second member, or the third memberrelative to at least one other of the first member, the second member,or the third member to interconnect vertebra; tracking a position of thefirst member while tracking a position of the second member in order toprovide a dynamic reference frame; displaying said position of each ofthe first member and the second member as two or more icons on adisplay; selecting a characteristic of at least one of the first member,the second member, or the third member; navigably positioning at leastone of the first member, the second member, or the third member relativeto another of at least one of the first member, the second member, orthe third member to achieve the selected final orientation withassistance of the two or more icons; and displaying a current positionicon relative to the two or more icons to illustrate the currentposition of at least one of the first member, the second member, or thethird member relative to said selected final orientation without imagesacquire of a patient.
 58. The method of claim 57, further comprising:positioning the first member and the second member substantially atleast one of percutaneously or minimally invasively into selectedanatomical vertebrae; and detecting a position of a navigational elementfixedly connected to said first member and said second member todetermine the position of the first member and the second member. 59.The method of claim 58, wherein said detector is selected from the groupcomprising an electromagnetic detector, an optical detector, aconductive detector, a fiber optic detector, an acoustic detector, andcombinations thereof.
 60. The method of claim 58, wherein the currentposition icon includes a progress bar illustrating the amount ofprogress of movement of the third member relative to at least one of thefirst member or the second member based on the selected characteristicand said selected final orientation.
 61. The method of claim 57, whereinat least one of the first member, the second member, or the third memberis selected from a group including a fastener, a rod, an acetabular cup,a femoral component, a tibial component, a glenoid component, a boneplate, and combinations thereof.
 62. The method of claim 57, whereindisplaying a position includes forming a graphical representation of thedetermined position of the first member and the second member anddisplaying it in user readable format.
 63. The method of claim 57,wherein selecting a characteristic of at least one of the first member,the second member or the third member includes selecting acharacteristic from a group including a length, a radius, a diameter, anoffset, a flexibility, an alignment, and combinations thereof with atleast an assistance of a processor by processing determined positions ofthe first member and the second member.
 64. The method of claim 57,further comprising: navigably positioning the third member including:moving a substantially steerable catheter relative to the first memberand the second member; and displaying a real time position of at least aportion of the third member relative to the first member or and thesecond member.
 65. The method of claim 57, wherein selecting the finalorientation includes selecting at least one of an alignment in a firstplane or an alignment in a second plane.
 66. The method of claim 65,further comprising positioning a fourth member relative to the firstmember and the second member to assist in achieving the selected finalorientation.
 67. The method of claim 66, further comprising: navigablypositioning the third member including: moving the third member relativeto at least one of the first member, the second member, or the fourthmember to substantially fix the construct in the selected finalorientation.
 68. The method of claim 57, further comprising: obtaining apatient image to verify the positioning of the first member, the secondmember, and the third member in the selected final orientation.
 69. Thesystem of claim 68, wherein said first member includes a screw with ashank and the adjustable head operable to be positioned into a vertebra;wherein said tracking element is operable to be connected to saidadjustable head; wherein said processor is operable to determine aposition of the adjustable head and display the first icon to illustratethe determined position of the adjustable head.
 70. The method of claim57, further comprising: selecting a pedicle screw for at least one ofthe first member, the second member, or the third member and a connectorfor at least one of another of the first member, the second member, orthe third member.
 71. The method of claim 70, wherein navigablypositioning at least one of the first member, the second member, or thethird member includes: positioning at least a first screw relative tosecond screw to allow for interconnection in a selected alignment. 72.The method of claim 70, wherein navigably positioning at least one ofthe first member, the second member, or the third member includes:displaying a movement of the connector relative to substantially only atleast one of the screws.
 73. The method of claim 57, wherein trackingcomprises tracking the position of the first member or the second memberwith six degrees of freedom.
 74. A method of implanting a constructhaving at least a first pedicle screw member, a second pedicle screwmember, and a third elongate rod member, the method comprising:positioning the first pedicle screw member into a boney structurevertebra; removably and fixedly connecting a first tracking element tothe first pedicle screw member; tracking a position of the first pediclescrew member in a selected space with the first tracking elementconnected to the first member; positioning the second pedicle screwmember relative to the first pedicle screw member in a second boneystructure vertebra; removably and fixedly connecting a second trackingelement to the second pedicle screw member while maintaining connectionof the first tracking element to the first pedicle screw member;tracking a position of the second pedicle screw member in the selectedspace with a second tracking element connected to the second member;determining an alignment in a first plane and an alignment in a secondplane of the first pedicle screw member and the second pedicle screwmember; navigating the third elongated rod member relative to the firstpedicle screw member and the second pedicle screw member, while trackingthe first tracking element connected with the first pedicle screw memberand tracking the second tracking element connected to the second pediclescrew member, including: removably and fixedly connecting a thirdtracking element to the third elongate rod member while maintaining theconnection of the first tracking element to the first pedicle screwmember and the second tracking element to the second pedicle screwmember; determining a characteristic of the third elongated rod memberto achieve the determined alignment in the first plane and the secondplane; determining a real time position of the third elongated rodmember relative to at least one of the first pedicle screw member or thesecond pedicle screw member with the respective connected first, second,and third tracking elements; and displaying a first member icon, asecond member icon, and a third member on a display to illustrate thedetermined real time position of the first pedicle screw member, thesecond pedicle screw member, and the third elongated rod member withoutdisplaying representations of the boney structure.
 75. The method ofclaim 74, further comprising displaying an entry point icon indicating apoint in space through which the tip of the third elongated member is topass.
 76. The method of claim 75, further comprising moving a navigableprobe in contact with an external soft tissue of a patient to determinea contour of the external soft tissue of the patient.
 77. The method ofclaim 76, further comprising: displaying a progress icon to representthe real time progress of the third member relative to achieving thedetermined characteristic of the third member.
 78. The method of claim76, further comprising: automatically determining an optimalcharacteristic with a processor of at least one of the first member, thesecond member or the third member including a length, a radius, adiameter, an offset, a flexibility, an alignment, and combinationsthereof.
 79. The method of claim 78, further comprising: automaticallydetermining with a processor the entry point through the external softtissue to achieve the selected characteristic.
 80. The method of claim79, wherein the optimal characteristic can be determined in real timebased on the tracked position of at least the first member, the secondmember or the third member.
 81. The method of claim 79, furthercomprising: removing all of the first tracking element, the secondtracking element, and the third tracking element from the respectivefirst pedicle screw member, the second pedicle screw member, and thethird elongated rod member after navigating the third elongate rodmember to achieve the selected alignment.